Acute Toxicity

Reproductive Effects

Beilstein Registry Number

Beilstein Handbook Reference

Compound Descriptor Code

Skin-rat LD50 Value (ng/kg)

Chemical Definition

Skin-rat LD50 Value (nL/kg)

Irritation Data

Status Lines (ATSDR, EPA, NIOSH, NTP and OSHA)

Inhalation-rat LC50 Value (ng/m3/4 hour)

Standards and Regulations

Inhalation-rat LC50 Value (ppb/4 hour)

Skin-rabbit LD50 Value (ng/kg)

Other Multiple Dose Toxicity Data

Skin-rabbit LD50 Value (nL/kg)

Tumorigenic Effects

Molecular Weight

Toxicology/Cancer Reviews

Molecular Weight (Whole Numbers)

Wiswesser Line Notation

NIOSH Criteria Documents

LD50/LC50 Values for orl-rat/skn-rat/skn-rbt/ihl-rat

Oral-rat LD50 Value (ng/kg)

Name Fragments

Each record in RTECS is assigned a unique Accession Number made up of 9 characters, the first two of which are alphabetic and the remainder numeric.  This allows you to retrieve a specific record at any time.  The first search example above actually retrieves the single record for Benzene.

Each number varies directly with the alphabetic sequence of the name, so that toluene, for example, has a higher number than benzene and the identifier is assigned alphabetically and numerically to each RTECS substance.  It is not intentionally related to the compound's toxicity or structure, although compounds with alphabetically similar names and, in some cases therefore, similar structures are grouped together.

The second search example given above finds all compounds containing zinc or zirconium in which these metals have been used to classify the substance.  Using RTECS numbers (as with CAS numbers (RN)) is particularly useful in narrowing down a search.

Using this field to get to a particular record is one of the fastest single substance retrieval methods.

This is one of the fields contained within the Citation list (CITN) - it is a unique identifier for the chemical substance.

Each unit or segment of data in this field sequentially includes the toxic effects code (TEC), the route of exposure, the species of animal studied, the type of dose, the amount of substance per body weight or concentration per unit of air volume and, where applicable, the duration of exposure and the reference from which the information was extracted.  An example of an acute toxicity data segment is given here:

A70-F41-Y01 orl-rat TDLo: 1282 mg/kg/90D-C
   Human & Experimental Toxicology.  (Macmillan Press Ltd., Brunel
   Road, Houndmills, Basingstoke, Hampshire, RG21 2XS, UK) V.9- 1990-
   13,353,1994 (HETOEA);

Each element of the acute toxicity data is discussed below.

A. Toxic Effects

The TECs listed in the Registry should not be viewed as an exhaustive representation of all the potential toxic effects of a compound.  Beginning in October 1980, a coding system was developed to include over 400 different effects.  These effects are noted in the Registry by means of an alphanumeric Toxic Effects Code (TEC).  The TEC permits a detailed coding of the toxic effects reported in the literature and is included for human and animal data.

In a data segment, the TEC is the first part of the entry; it appears to the left of the route of administration.  Each TEC is made up of one or more code segments (separated from each other by hyphens), each of which contains three characters (alphabetic-numeric-numeric).  Each TEC may contain as many as three code parts.  In the above example the TEC is A70-F41-Y01 and is thus composed of 3 parts.

The first position of each segment is alphabetic and describes an organ, tissue or functional system, or other major physiological or behavioral grouping.  Positions two and three are numeric damage codes that specify individual toxic effects within each system.  For the above example it can be deduced that the 'A' in A70 refers to 'Brain and Coverings' and that the '70' refers to 'changes in brain weight' for the first code part.  Similarly 'F' refers to the 'Behavioral Functional System' and the '41' refers to 'alteration of operant condition'; 'Y' refers to the 'Biochemical Functional System' and '01' to true cholinesterase.

In using the TEC, the reader should be aware of the following restrictions:

 - specific TECs included in the data may change as more experience is gained in coding the literature.  Some may be deleted, while others may be added.  The TEC is not static and will be changed to reflect the information reported in the literature.

 - TECs listed in each line describe effects reported only for the route and species specified on that line.

 - the TECs listed in the Registry should not be viewed as an exhaustive representation of all the potential toxic effects of a compound.  This caution results from two considerations.  The first is that each segment is limited to a maximum of three code parts.  For studies in which more than three effects were reported, only those deemed most significant are listed.  Second, the effects are limited to those that meet the basic selection criteria for inclusion in the Registry, i.e., lowest dose for a given route-species combination.  Unique effects reported in studies not cited in the Registry would, therefore, not be listed herein.  This restriction is important because, for example, studies done to determine acute LD50 values often report little other information besides the LD50 itself.

Sometimes no TECs appear in the data segment.  Rather, the phrase 'T/E unlistd'.  This means that the reference was reviewed but contained no description of toxic effects other than the lethal dose value listed.

B. Route of Exposure or Administration.

Although many exposures to substances in the industrial community occur via the respiratory tract or skin, most studies in the published literature report exposures of experimental animals in which the test substances were introduced primarily through the mouth by pills, in food, in drinking water, or by intubation directly into the stomach.  The abbreviations and definitions of the various routes of exposure reported in the Registry are found elsewhere in this guide.

In the example given at the top of this section, the route is given as 'orl' which is oral.

C. Species Exposed.

Since the effects of exposure of humans are of primary concern, it is indicated, when available, whether the results were observed in man, woman, child, or infant.  If no such distinction was made in the reference, the abbreviation "hmn" (human) is used.  However, the results of studies on rats or mice are the most frequently reported and hence provide the most useful data for comparative purposes.  The species and abbreviations used in reporting toxic dose data are presented elsewhere in this guide.

In the example given at the top of this section the species is given as 'rat' which is rat.

D. Description of Exposure.

Six abbreviations are used to describe the administered dose reported in the literature.  These abbreviations indicate whether the dose caused death (LD) or other toxic non-lethal effect (TD), or whether it was administered as a lethal concentration (LC) or toxic concentration (TC) in the inhaled air.  In general, the term "Lo" is used where the number of subjects studied was not a significant number from the population or the calculated percentage of subjects showing an effect was listed as 100.  The doses and concentrations are defined as follows:

 - TDLo - Toxic Dose Low - The lowest dose of a substance introduced by any route, other than inhalation, over any given period of time and reported to produce any toxic effect in humans or to produce tumorigenic, reproductive, or multiple dose effects in animals.

 - TCLo - Toxic Concentration Low - the lowest concentration of a substance in air to which humans or animals have been exposed for any given period of time that has produced any toxic effect in humans or produced tumorigenic, reproductive, or multiple dose effects in animals.

 - LDLo - Lethal Dose Low - the lowest dose (other than LD50) of a substance introduced by any route, other than inhalation, over any given period of time in one or more divided portions and reported to have caused death in humans or animals.

 - LD50 - Lethal Dose Fifty - a calculated dose (given all at once) of a substance which is expected to cause the death of 50% of an entire defined experimental animal population.  It is determined from the exposure to the substance by any route other than inhalation of a significant number from that population.  Testing is most often done with rats or mice and LD50 values are usually expressed in terms of the amount of chemical administered (e.g. milligrams) per kilogram of the animal's weight.  The LD50 can be found for any route of administration but dermal (applied to the skin) and oral (given by mouth) methods are the most common.  LD50/LC50 (see below) values are important because chemicals can have a wide range of effects on our health.  The provide a means of comparing the acute toxicity of chemicals.  Acute toxicity can be defined as the ability of a chemical to cause ill effects relatively soon after a 4-hour exposure to a chemical in the air or one oral administration.  "Relatively soon" is normally defined as a period of minutes, hours (up to 24) or days (up to around 2 weeks) but rarely longer.

Other lethal dose percentages, such as LD1, LD10, LD30, and LD99, may be published in the scientific literature for the specific purposes of the author.  Such data would be published in the Registry if these figures, in the absence of a calculated lethal dose (LD50), were the lowest found in the literature.

 - LCLo - Lethal Concentration Low - the lowest concentration of a substance in air, other than LC50, which has been reported to have caused death in humans or animals.  The reported concentrations may be entered for periods of exposure which are less than 24 hours (acute) or greater than 24 hours (subacute and chronic).

 - LC50 - Lethal Concentration Fifty - a calculated concentration of a substance in air, exposure to which for a specified length of time is expected to cause the death of 50% of an entire defined experimental animal population.  It can also mean the concentration of a chemical in water for environmental studies.  It is determined from the exposure to the substance of a significant number from that population.

Sometimes just LD or LC designations appear in this field and these refer to maximum tolerated doses or concentrations respectively.  This data usually contains no description of toxic effects in the reference (T/E unlistd - see above).

TDLo is used in the example at the top of this section.

E. Units of Dose Measurement.

As in almost all experimental toxicology, the doses given are expressed in terms of the quantity administered per unit body weight, or quantity per skin surface area, or quantity per unit volume of the respired air.  In addition, the duration of time over which the dose was administered is also listed, as needed.

            Dose amounts are generally expressed as milligrams per kilogram (mg/kg).  In some cases, because of dose size and its practical presentation in the file, grams per kilogram (gm/kg), micrograms per kilogram (ug/kg), or nanograms per kilogram (ng/kg) are used.  Volume measurements of dose were converted to weight units by appropriate calculations.  Densities were obtained from standard reference texts.  Where densities were not readily available, doses were reported as milliliters/kilogram (ml/kg).

            All body weights are converted to kilograms (kg) for uniformity.  For those references in which the dose was reported to have been administered to an animal of unspecified weight or a given number of animals in a group (e.g., feeding studies) without weight data, the weights of the respective animal species are assumed to be those listed in the species table and the dose listed on a per kilogram body weight basis.  Assumptions for daily food and water intake are also found therein to allow approximating dosages for humans and experimental animals where the dose was originally reported as a concentration in food or water.  The values presented are selections which are reasonable for the species and convenient for dose calculations.

            Concentrations of a gaseous substance in air are generally listed as parts of vapor or gas per million parts of air by volume (ppm).  However, parts per hundred (pph or per cent), parts per billion (ppb) or parts per trillion (ppt) may be used for convenience of presentation.  If the substance is a solid or a liquid, the concentrations are listed preferably as milligrams per cubic meter (mg/m3) but may, as applicable, be listed as micrograms per cubic meter (ug/m3), nanograms per cubic meter (ng/m3) or picograms per cubic meter (pg/m3) of air.  For those cases in which other measurements of contaminants are used, such as the number of fibers or particles, the measurement is spelled out.

The dose amount used in the example at the top of this section is mg/kg.

F. Duration of Exposure.

The duration of exposure is included to give an indication of the testing period during which the animal was exposed to the total dose.

Where the duration of exposure is available, time is presented as minutes (M), hours (H), days (D), weeks (W) or years (Y).  Additionally, continuous (C) indicates that the exposure was continuous over the time administered, such as ad libitum feeding studies or 24-hour, 7-day per week inhalation exposures.  Intermittent (I) indicates that the dose was administered during discrete periods, such as daily, twice weekly, etc.  In all cases, the total duration of exposure appears first after the kilogram body weight and slash, followed by descriptive data; e.g., 10 mg/kg/3W-I means ten milligrams per kilogram body weight administered over a period of three weeks, intermittently in a number of separate, discrete doses.  This description is intended to provide the reader with enough information for an approximation of the experimental conditions, which can be further clarified by studying the reference cited.

In the example given at the top of this section we have 90D-C which means that exposure was continuous over a 90 day period.

G. Frequency of Exposure.

Frequency of exposure to the test substance varies depending on the nature of the experiment.  For the purposes of the Registry, frequency of exposure is given for inhalation experiments, for human exposures (where applicable), or where reproductive, tumorigenic, or other multiple dose data are specified and so this data rarely appears in this field.

Each unit of data is accompanied by a detailed reference - these are discussed in detail in the section on references.

The first two search examples given above retrieve records containing specific TECs.  The third example does the same but limits the search to include those references containing an LD50 value.  Note that the 'near2' operator ensures that both C18 and LD50 occur together in the same segment of data within the AT field.  Use of the near operator could give false hits if there were several different pieces of data with the same reference as all the pieces and the reference are now considered to be a sentence (as far as the SPIRS search engine is concerned).

The fourth search example is useful in that it will - find very low LD50 values (1 ug/kg to 99 ug/kg).  The adj operator ensures that the search engine finds the terms adjacent to each other and in the order specified.  The near1 operator ensures the numeric part is of the right form and right next to 'LD50' (i.e. within 1 word - near1).  This is important in the case where there is more than one segment of data associated with a single reference.  The use of brackets ensures the search engine performs the correct search by executing the sub-searches within the innermost matching brackets first.  This search could be further narrowed down by specifying a species and/or route of administration.  The fifth example is similar but returns LD50 values quoted in nL/kg or ng/kg.

However, looking for low LD50 or LC50 (for common route-species combinations) is probably better achieved by retrieval on one or more of the eight specially developed fields by extraction from the Acute Toxicity data - see the LD50/LC50 range searchable fields topic for more information.

The Beilstein Registry Number (BRN) is assigned when an organic compound is registered for the first time in the Beilstein database.  The registration procedure is based on the available structural information for a substance which is included in the connection table.  The BRN (as well as the chemical structure) of a substance are unambiguous identifiers.

Nearly 47000 RTECS records contain a reference to the Beilstein Registry Number (December 2003).

As the BRN can identify a substance, it is included in the Citation list of fields for this database.

The Beilstein Handbook Reference is also a field in RTECS.

The Beilstein Handbook Reference (BHR) contains information about the organic substance already printed in the Beilstein Handbook.  This reference format consists of a four-part number of the form a-bb-cc-ddddd where:

 'a' denotes the series,
 'bb' the volume,
 'cc' the subvolume and
 'ddddd' the page number.

Each component of this reference is zero-filled from the left as necessary.

The basic series, covering the literature up to 1910, is given a series number of 0; supplementary series are denoted from 1 to 5.  There are no subvolumes in supplementary series 4.  Note that 2 or more substances can have the same BHR.

About 21,500 records contain this field (January 2001).

Beilstein Registry Numbers are also included in RTECS.

This field contains an alphabetic code and the associated compound description.  These classes (or compound descriptor codes) are listed below and can be used as selection keys to extract defined subfiles of the master file (see the first search example above):

A - Agricultural Chemical
C - Tumorigen
D - Drug
H - Hormone
M - Mutagen
N - Natural Product
O - Organometallic
P - Human Data
S - Primary Irritant
T - Reproductive Effector
Z - Other

More than one code can be attributed to a particular substance.  If a record contains no code, a value of Z - Other is attributed to the substance.  This means that this field is always populated with some value.

The RTECS compound descriptor codes do not represent an evaluation of the toxicity of a substance, nor are the codes all-inclusive with respect to use (that is, there may be some substances in the RTECS file that should be, but are not, coded as belonging to certain application classes).  The codes must be interpreted only in conjunction with the other information found in each substance data record.

The RTECS descriptor codes fall into two categories: (1) those based on the types of toxicity data found in the substance data records and (2) those based on related information found in the references from which the data were extracted.  In the first category are the following descriptor codes: tumorigen, mutagen, reproductive effector, primary irritant, and human data.  As mentioned, these five classifications do not represent an evaluation of the overall toxicity of a substance by NIOSH.  Rather, they indicate the type(s) of toxicity data found in the substance record.

The descriptor code "tumorigen" is something of a misnomer.  More specifically, it denotes a "substance with positive or negative tumorigen reference(s)".  That is, any substance with the descriptor code "tumorigen" will have one or more of the following in its RTECS data record:

 - One or more pieces of tumorigenic data.

 - One or more U.N. International Agency for Research on Cancer (IARC) review data segments, regardless of whether the IARC review concluded that the carcinogenicity of the substance was noted as Sufficient Evidence, Limited Evidence, Inadequate Evidence, or No Evidence.

 - One or more National Toxicology Program (NTP) carcinogenesis bioassay studies status data segments, regardless of whether the substance had only been selected for test or whether the NTP study showed Clear Evidence, Some Evidence, Equivocal Evidence, or No Evidence of Carcinogenicity, or that the test is still in progress.

Based on the above criteria, therefore, there may be some substances in RTECS that have only negative IARC reviews or NTP status data, but that still appear with the descriptor code "Tumorigen".  This is done to bring the significance of the results of the IARC reviews and the NTP studies to the user's attention.  Again, this points out the need to review the complete data record before drawing any conclusion about the total toxic potential of a substance.  The user must not rely solely on the descriptor code.

Any substance with the descriptor code "Reproductive-Effector" will contain:

 - One or more reproductive effects data segments or

 - One or more tumorigenic data segments that cite either transplacental carcinogenesis (Toxic Effects Code [TEC] T65) or tumors to the reproductive system (TEC T61, T62, T63, T64, or T69).  Thus, a substance reported to cause these latter two types of effects will contain both tumorigen and reproductive effector compound descriptor codes.

Any substance described as a "primary irritant" will contain one or more skin or eye irritation data segments in its RTECS record.

The descriptor code "Human-Data" was added recently to RTECS and covers ALL human species data (hmn - human, man - man, wmn - woman, chd - child and inf - infant).  Using this code will yield ALL human-related data not just 'hmn' species data.

The remaining five descriptor codes (agricultural chemical, drug, organometallic, hormone, and natural product) are use or application codes and are included in the file based only on information found in the references cited in RTECS.  For example, if an article that reports an oral-rat LD50 value for a substance indicates the substance is used as a drug or a pesticide, then it will be so coded in the file.  However, if the article makes no such indication, descriptor codes will not be added to the data record.  Therefore, the user should recognize that these classifications are not all-inclusive; they are based solely on information in the references from which the RTECS is compiled.

Agricultural chemicals include those used to improve crop yields, such as fertilizers and pesticides of all kinds.  Drugs include both commercially available (approved) compounds, as well as those that have been identified as experimental.  Hormones include both those naturally found in the body and synthetic substances that act like hormones.  Natural products include organic compounds that are produced by plants, animals and microorganisms, and that are not commercially synthesized.

This field is useful for refining a search and reduce the number of records as it can only hold a small number of values.  See the examples given at the top of this section.  Codes can be combined as in the third example which will retrieve all the substances classed as either mutagens or tumorigens.  Note the use of brackets; without them the search on 'm' will not be performed on this field but on the general free text index.

The CD field contains additional information not present either in the Prime Name of Subsatnce or Synonym(s) fields and is usually included for those substances of ill-defined or questionable composition such as plant or animal extracts; it is also used to describe natural products.

The data in this field includes the source of the substance, a general statement of constituents, or other pertinent information, and the CODEN citation of the reference that contained the definition.

Each segment of data includes, in sequence, the tissue tested (skin or eye), the species of animal tested, the total dose and where applicable, the duration of exposure; for skin tests only, whether open or occlusive (if the word ''open" is not present, it can be assumed that the test site is occlusive) an interpretation of the irritation response severity when noted by the author; and the reference from which the information was extracted.  Only positive irritation test results are included in the Registry.

Here is one of the segments for morpholine (January 2001 data):

skn-rbt 500 mg open MOD
 - Union Carbide Data Sheet.  (Union Carbide Corp., 39 Old Ridgebury
 - Rd., Danbury, CT 06817)  4/21/1967 (UCDS**)

Note that the tissue, the species and interpretation of the irritation response severity (see below) (skin, rabbit and moderate respectively in this case) are presented in abbreviated form.

Substances that are applied topically to the skin or to the mucous membranes can elicit either (a) systemic effects of an acute or chronic nature or (b) local effects, more properly termed "primary irritation".  A primary irritant is a substance that, if present in sufficient quantity for a sufficient period of time, will produce a non-allergic, inflammatory reaction of the skin or of the mucous membrane at the site of contact.  Primary irritants are further limited by the Editor to those substances that are not corrosive.  Hence, concentrated sulfuric acid is not classified as a primary irritant.

a). Primary Skin Irritation.

In experimental animals, a primary skin irritant is defined as a chemical substance that produces an irritant response on first exposure in a majority of the test subjects.  However, in some instances compounds act more subtly and require either repeated contact or special environmental conditions (humidity, temperature, occlusion, etc.) to produce a response.

The most standard animal irritation test is the Draize procedure (Journal of Pharmacology and Experimental Therapeutics, 82: 377-390, 1944).  This procedure has been modified and adopted as a regulatory test by the Consumer Product Safety Commission (CPSC) in 16 CFR 1500.41 (formerly 21 CFR 191.11).  In this test a known amount (0.5 ml of a liquid or 0.5 gm of a solid or semisolid) of the test substance is introduced under a one square inch gauze patch.  The patch is applied to the skin (clipped free of hair) of twelve albino rabbits.  Six rabbits are tested with intact skin and six with abraded skin.  The abrasions are minor incisions made through the stratum corneum, but are not sufficiently deep to disturb the dermis or to produce bleeding.  The patch is secured in place with adhesive tape, and the entire trunk of the animal is wrapped with an impervious material, such as rubberized cloth, for a 24-hour period.  The animal is immobilized during exposure.  After 24 hours the patches are removed and the resulting reaction evaluated for erythema, eschar, and edema formation.  The reaction is again scored at the end of 72 hours (48 hours after the initial reading), and the two readings are averaged.  A substance producing any degree of positive reaction is cited in the Registry as an irritant.

As the modified Draize procedure described above has become the standard test specified by the U.S. Government, nearly all of the primary skin irritation data either strictly adhere to the test protocol or involve only simple modifications to it.  When test procedures other than those described above are reported in the literature, appropriate codes are included in the irritation data segment to indicate those deviations.

The most common modification is the lack of occlusion of the test patch, so that the treated area is left open to the atmosphere.  In such cases, the notation "open" appears in the data segment.  Another frequent modification involves whole arm or whole body immersion in the test substance or, more commonly, in a dilute aqueous solution of the test substance.  This type of test is often conducted on soap or detergent solutions.  Immersion data are identified by the abbreviation "imm" in the data segment.

The dose reported is based first on the lowest dose producing an irritant effect and second on the latest study published.  The dose is expressed as follows:

 - Single application by the modified Draize procedure is indicated by only a dose amount.  If no exposure time is given, then the data are for the standard 72-hour test.  For test times other than 72 hours, the dose data are given in mg (or in an appropriate unit)/duration of exposure, e.g. 10 mg/24H.

 - Multiple applications involve administration of the dose in divided portions applied periodically.  The total dose of test substance is expressed in mg (or appropriate unit)/duration of exposure, with the symbol "I" indicating intermittent exposure, e.g., 5 mg/6D-I.

For more information regarding the duration and frequency of exposure please refer to the acute toxicity field (AT).

The method of testing substances for primary skin irritation given in the Code of Federal Regulations does not indicate an interpretation of the response.  However, some authors do include a subjective rating of the irritation observed.  If such a severity rating is given, it is included in the data segment as mild ("MLD"), moderate ("MOD"), or severe ("SEV").  The Draize procedure employs a rating which is included here for informational purposes only since other researchers may not categorize response in this manner.

 - Mild (MLD; well defined erythema and slight edema (edges of area well defined by definite raising)
 - Moderate (MOD; moderate to severe erythema and moderate edema (area raised approximately 1 mm)
 - Severe (SEV; severe erythema (beet redness) to slight eschar formation (injuries in depth) and severe edema (raised more than 1 mm and extending beyond area of exposure).

b). Primary Eye Irritation.

In experimental animals, a primary eye irritant is defined as a chemical substance that produces an irritant response in the test subject on first exposure.  Eye irritation study procedures developed by Draize have been modified and adopted as a regulatory test by CPSC in 16 CFR 1500.42.  In this procedure, a known amount of the test material (0.1 ml of a liquid or 100 mg of a solid or paste) is placed in one eye of each of six albino rabbits; the other eye remains untreated, serving as a control.  The eyes are not washed after instillation and are examined at 24, 48, and 72 hours for ocular reaction.  After the recording of ocular reaction at 24 hours, any or all eyes may be further examined, following the application of fluorescein.  Any or all of eyes may also be washed with a sodium chloride solution (U.S.P. or equivalent) after the 24-hour reaction has been recorded.

A test is scored positive if any of the following effects are observed: (1) ulceration (besides fine stippling); (2) opacity of the cornea (other than slight dulling of normal luster); (3) inflammation of the iris (other than a slight deepening of the rugae or circumcorneal injection of the blood vessel); (4) swelling of the conjunctiva (excluding the cornea and iris) with eversion of the eyelid; or (5) a diffuse crimson-red color with individual vessels not clearly identifiable.  A substance is an eye irritant if four of six rabbits score positive.  It is considered a nonirritant if none or only one of six animals exhibits irritation.  If intermediate results are obtained, the test is performed again.  For the purpose of RTECS, substances producing any degree of irritation in the eye are identified in the Registry as irritants.  When an author has designated a substance as a mild, moderate, or severe eye irritant, this designation is also reported.

The dose reported is based first on the lowest dose producing an irritant effect and second on the latest study published.  Single and multiple applications are indicated as described in a). above.  Test times other than 72 hours are noted in the dose.  All eye irritant test exposures are assumed to be continuous, unless the reference states that the eyes were washed after instillation.  In this case, the notation "rns" (rinsed) is included in the data segment.

c). Species Exposed.

Since Draize procedures for determining both skin and eye irritation specify rabbits as the test species, most of the animal irritation data in the Registry are for rabbits, although any of the species may be used.  The Editor endeavors to include as much human data as possible since this information is directly applicable to occupational exposure.  Much of this data comes from studies conducted on volunteers (such as the cosmetic or soap ingredients) or from persons accidentally exposed.  When an accidental exposure, such as a spill, is cited, the data segment includes the abbreviation "nse" (non-standard exposure).  In these cases it is often very difficult to determine the precise amount of the substance to which the individual was exposed.  Therefore, for accidental exposures an estimate of the concentration or the strength of the substance, rather than a total dose amount, is generally provided.

The first search example above finds those records when an accidental exposure or spill was cited.

The second example finds those records where a SEVERE severity rating on humans was reported in the reference (for either skin or eye tests).  The near4 operator ensures that the two terms occur in the same data segment (and within 4 words of each other) and is important in those cases where there may be several segments in the same 'sentence' (as far as the search engine is concerned) due to duplicate references.  The use of the near operator may lead to additional 'false' hits as it may combine data from different segments.

This is one of the fields created from the original RTECS Acute Toxicity data which permits comparison of integer-based LC50 values (4 hour exposure) for this route-species combination.  In order to provide such a retrieval capability it has been necessary to scale and normalise the values.  Nevertheless, where this field occurs, it is accompanied by the same value in mg/m3/4H in square brackets together with the applicable Toxic Effect Codes.  For example for vanadic acid, ammonium salt, February 2001 data, the contents of the IHNG field were:

7800000 ng/m3/4H. [7.800000 mg/m3/4H] F07-K12-U26

Please note that only the first integer displayed is indexed.

If ever a value is too large for the SPIRS search engine to handle a value of 999999999999 appears (although the true value appears within square brackets).  The search example given above finds those LC50 values for inhalation-rat which are less than 8 mg/m3/4H.  In the construction of this field, indeterminate values (i.e. LC50 > ...) are ignored.  Please also note that in selecting such data, MDL always selects the lowest available from the literature.

Looking at the field-specific limit index for the IHNG field will quickly reveal the most lethal substances in this context (lowest LC50 values).

For more general information about LC50 values click here.

This is one of the fields created from the original RTECS Acute Toxicity data which permits comparison of integer-based LC50 values (4 hour exposure) for this route-species combination.  In order to provide such a retrieval capability it has been necessary to scale and normalise the values.  Nevertheless, where this field occurs, it is accompanied by the same value in ppm/4H in square brackets together with the applicable Toxic Effect Codes.  For example, Pentaborane(9), February 2001 data, the contents of the IHPB field were:

6000 ppb/4H. [6.000000 ppm/4H] T/E unlistd

Please note that only the first integer displayed is indexed.

If ever a value is too large for the SPIRS search engine to handle a value of 999999999999 appears (although the true value appears within square brackets).  The search example given above finds those LC50 values for inhalation rat which are less than 10 ppm/4H.  In the construction of this field, indeterminate values (i.e. LC50 > ...) are ignored.  Please also note that in selecting such data, MDL always selects the lowest available from the literature.

Looking at the field-specific limit index for the IHPB field will quickly reveal the most lethal substances in this context (lowest LC50 values).

For more general information about LC50 values click here.

References in this field include the results of multiple dose toxicity studies, of variable duration, which relate to other than mutagenic, reproductive, or tumorigenic effects.  The format is similar to that found in the tumorigenic effects field, where toxic rather than lethal doses are indicated, including duration of exposure.  The numerical dose data is a cumulative amount over the duration of the study.  The most common study designs include thirteen-week, twenty-six week, fifty-two week, and two-year studies.  Because the effects described in this field are nonlethal, the TECs assume an important descriptive role.

The categories of toxicity data entry that can occur in this field are TDLo (single or multiple dose, any route of exposure except inhalation and all non-lethal studies for both humans and animals) and TCLo (single or multiple dose, inhalation as the only route of exposure, and all non-lethal studies for both humans and animals).

The first search example above (vo1 in md) finds those multiple dose toxicity studies for which the TEC is deemed carcinogenic by RTECS criteria whilst the second search (7d-c in md) could be a useful limiting term to narrow down searches to 7-day continuous studies.

Mutation data include both whole animal and in vitro studies.  Each mutation data segment includes, in sequence, the mutation test system utilized, the species of tested organism (and, where applicable, the route of administration or cell type), the exposure concentration or dose, and the reference from which the information was extracted.  Only positive mutation test results are cited in RTECS.

A mutation is defined as any heritable change in genetic material.  Unlike irritation, reproductive effects, tumorigenic, acute, and other multiple dose toxicity data, which report the results of whole animal studies, mutation data also include studies on lower organisms such as bacteria, yeasts, molds, and insects, as well as in vitro mammalian cell cultures.  Studies of plant mutagenesis are not now included in the Registry.  No attempt is made to evaluate the significance of the data or to rate the relative potency of the compound as a mutagenic risk to man.

An example of a mutation data segment appears below:

dna-mus-fbr 16 mg/L
   Mutation Research.  (Elsevier Science Pub. B.V., POB 211,
   1000 AE Amsterdam, Netherlands) V.1-  1964-  222,223,1989 (MUREAV)

a. Mutation Test System

A number of test systems are used to detect genetic alterations caused by chemical substances.  Those systems currently cited in the Registry are listed below.  Others found in the literature have been grouped together under the general term "other mutation test system" (oms).  Each test system is identified by the 3-letter code shown in parentheses.  For additional information about mutation tests, the reader may wish consult the Handbook of Mutagenicity Test Procedures, edited by B.J. Kilbey, M. Legator, W. Nichols, and C. Ramel (Amsterdam: Elsevier, Second Edition, 1984).

            Mutation in Microorganisms (mmo) - system is based on the detection of heritable genetic alterations in microorganisms exposed directly  the chemical substance.  An enzymatic activation step is automatically included in the test procedure.  To differentiate between early tests in which the activation step was not an automatic inclusion, the notation "+S9" or "-S9" will appear in the segment.

            Micronucleus Test (mnt) - system utilizes the fact that chromosomes or chromosome fragments may not be incorporated into one or the other of the daughter nuclei during cell division.

            Specific Locus Test (slt) - system utilizes a method for detecting and measuring rates of mutation at any or all of several recessive loci.

            DNA Damage (dnd) - system detects the damage to DNA strands, including strand breaks, crosslinks, and other abnormalities.

            DNA Repair (dnr) - system utilizes methods of monitoring DNA repair as a function of induced genetic damage.

            Unscheduled DNA Synthesis (dns) - system detects the synthesis of DNA during usually non-synthetic phases.

            DNA Inhibition (dni) - system detects inhibition of DNA synthesis.

            Gene Conversion and Mitotic Recombination (mrc) - system utilizes unequal recovery of genetic markers in the region of the exchange during genetic recombination.

            Cytogenetic Analysis (cyt) - system utilizes cultured cells or cell lines to assay for chromosomal aberrations following the administration of chemical substances.

            Sister Chromatid Exchange (sce) - system detects the interchange of DNA in cytological preparations of metaphase chromosomes between replication products at apparently homologous loci.

            Sex Chromosome Loss and Nondisjunction (sln) - system measures the nonseparation of homologous chromosomes at meiosis and mitosis.

            Dominant Lethal Test (dlt) - a dominant lethal is a genetic change in a gamete that kills the zygote produced by that gamete.  In mammals, the dominant lethal test measures the reduction of litter size by examining the uterus and noting the number of surviving and dead implants.

            Mutation in Mammalian Somatic Cells (msc) - system utilizes the induction and isolation of mutants in cultured mammalian cells by identification of the gene change.

            Host-Mediated Assay (hma) - system uses two separate species, generally mammalian and bacterial, to detect heritable genetic alteration caused by metabolic conversion of chemical substances administered to host mammalian species in the bacterial indicator species.

            Sperm Morphology (spm) - system measures the departure from normal in the appearance of sperm.

            Heritable Translocation Test (trn) - test measures the transmissibility of induced translocations to subsequent generations.  In mammals, the test uses sterility and reduced fertility in the progeny of the treated parent.  In addition, cytological analysis of the F1 progeny or subsequent progeny of the treated parent is carried out to prove the existence of the induced translocation.  In Drosophila, heritable translocations are detected genetically using easily distinguishable phenotypic markers, and these translocations can be verified with cytogenetic techniques.

            Morphological Transformation (mtr) - system utilizes morphological criteria to detect cytological differences between normal and transformed tumorigenic cells.

            Phage Inhibition Capacity (pic) - system utilizes a lysogenic virus to detect a change in the genetic characteristics by the transformation of the virus from noninfectious to infectious.

            Body Fluid Assay (bfa) - system uses two separate species, usually mammalian and bacterial.  Test substance is first administered to host, from whom body fluid (e.g., blood or urine) is subsequently taken.  This body fluid is then tested in vitro, and mutations are measured in the bacterial species.

            DNA Adduct (dna) - system detects the covalent bonding of chemical substances to DNA through the identification of modified nucleotides.  This is used in the example given above.

b. Species Peculiar to Mutation Data

Such species in RTECS are shown by their 3-letter codes shown in the following list.  Other species are listed in the species section.

Bacteria:

bcs - Bacillus subtilis
esc - Escherichia coli
hmi - Haemophilus influenzae
klp - Klebsiella pneumoniae
sat - Salmonella typhimurium
srm - Serratia marcescens

Molds:

asn - Aspergillus nidulans
nsc - Neurospora crassa

Yeasts:

smc - Saccharomyces cerevisiae
ssp - Schizosaccharomyces pombe

Protozoa:

clr - Chylamydomonas reinhardi
eug - Euglena gracilis
omi - Other microorganisms

Insects:

dmg - Drosophila melanogaster
dpo - Drosophila pseudo-obscura
grh - Grasshopper
slw - Silkworm
oin - Other insect

Fish:

sal - Salmon
ofs - Other fish

If the test organism is a cell type from a particular species (generally mammalian), the parent species is reported, followed by a hyphen and the cell type designation.  For example, human leukocytes are coded "hmn-leu".  The various cell types currently cited in the Registry are listed below:

ast - Ascites tumor
bmr - Bone marrow
emb - Embryo
fbr - Fibroblast (used in the example above)
hla - HeLa cell
kdy - Kidney
leu - Leukocyte
lng - Lung
lvr - Liver
mmr - Mammary gland
tes - Testis
oth - Other cell types not listed above

In the case of host mediated (hma) and body fluid assays (bfa), the host and indicator organisms are given as follows: host organism-indicator organism, e.g., "ham-sat" for a test in which hamsters were exposed to the test chemical and salmonella typhimurium was used as the indicator organism.

For in vivo mutagenic studies, the route of administration is specified following the species designation, e.g., "mus-orl" for oral administration to mice.  The route of administration is not specified for in vitro data.

c. Units of Exposure

The lowest dose producing a positive effect is cited.  The author's calculations are used to determine the lowest dose at which a positive effect was observed.  If the author fails to state the lowest effective dose, two times the control dose will be used.  Ideally, the dose should be reported in universally accepted toxicological units such as milligrams of test chemical per kilogram of test animal body weight.  While this is possible when the actual intake of a chemical by an organism of known weight is reported, it is not possible in many systems using insect and bacterial species.  When a dose is reported or where the amount can be converted to a dose unit, it is normally listed as milligrams per kilogram (mg/kg).  However, micrograms (ug), nanograms (ng), or picograms (pg) per kilogram may also be used for convenience of presentation.  Concentrations of gaseous substances in air are listed as parts per hundred (pph), million (ppm), billion (ppb), or trillion (ppt).

Test systems using microbial organisms usually report exposure data as an amount of chemical per liter (L), or amount per plate, well, or disc.  The amount may be on a weight (gm, mg, ug, ng, or pg) or molar (millimole [mmol], micromole [umole], nanomole [nmole], or picomole [pmole]) basis.  These units describe the exposure concentration rather than the dose actually taken up by the test species.  Insufficient data currently exist to permit the development of dose amounts from this information.  In such cases, therefore, the substance concentration units used by the author are reported.

Since the exposure values reported in host-mediated assays are the doses delivered to the host organism, no attempt is made to estimate the exposure concentration to the indicator organism.  The exposure values cited for host-mediated assay data are in units of milligrams (or other appropriate unit of weight) of substance administered per kilogram of host body weight or in parts of vapor or gas per million (ppm) parts of air (or other appropriate concentration) by volume.

The first search example given above retrieves references of mutagenic effects data studies involving the liver.

The second search finds test studies in which hamsters were exposed to the test chemical and salmonella typhimurium was used as the indicator organism.  Note that the search phrase 'ham-sat' will not reveal any hits because the mutation test system will precede 'ham'; hyphenated phrases are indexed as a whole and the individual components as well and the use of the near2 operator ensures the terms 'ham' and 'sat' will be adjacent to each other.

This field contains the molecular formula designating the elemental composition of the substance and is structured according to the Hill System (See Journal of the American Chemical Society, 22(8):478-494, 1900), in which carbon and hydrogen (if present) are listed first, followed by the other elemental symbols in alphabetical order.  The formulas for compounds that do not contain carbon are ordered strictly alphabetically by elemental symbol.  Compounds such as salts or those containing waters of hydration have molecular formulas incorporating the CAS dot-disconnect convention, in which the components are listed individually and separated by a period.  The individual components of the formula are generally given in order of decreasing carbon atom count and component ratios.  A lower case "x" indicates that the ratio is unknown.  A lower case "n" indicates a repeating polymer-like structure.  The formula is obtained from one of the cited references or a chemical reference text, or is derived from the name of the substance.

Fragmentary chemical structure searches can be done in this field because each component of the hyphenated phrase is indexed separately as well as the whole.  Searches can be limited to a particular family or group of compounds, e.g. ((cl or cl2) and c6) in mf retrieves all singly or doubly chlorinated organics with 6 carbon atoms.  Numbers which precede fragments have been separated by a space so that the fragments are searchable, e.g. 3Fe is represented as 3 Fe.  Omit full stops when searching in this field; round brackets, '(' and ')' should be substituted with a space.  See the section on indexable characters and searching for further information.

The first search example above finds those substances with exactly 40 carbon atoms in the formula whereas the second example finds those substances in RTECS which contain both chlorine and flourine atoms in their formula.

This is one of the fields contained within the Citation list (CITN).

The MW field contains the molecular weight of the substance where given.  It is calculated from the molecular formula using standard elemental atomic weights (carbon = 12.01).

The MW field consists of the following fields:

Molecular Weight (Whole Numbers)  (MWW)
Molecular Weight (With Decimals)  (MWX)

The MWW field holds the integer part of the molecular weight and its data is used for the MW index.  It is hidden from view deliberately so searches on it from either the find/search prompt or the index will NOT highlight the hits.  On the other hand the MWX data is displayed as the MW field.  This arrangement exists to permit integer range-searching on this data.

You can search the MW field with the following operators, as well as with in and =:

This is one of the fields contained within the Citation list (CITN).

The MWW field contains the integer part of the original RTECS value for the molecular weight.  It is indexed but not displayed.  Please refer to the MW field for more information.

The MWX field contains the molecular weight of the substance.  It is displayed in records but is not searchable.  Please refer to the MW field for more information.

This field contains NIOSH Standards Development and Surveillance Data generated by NIOSH in two areas of endeavour.  The Standards Development Programs produces Recommended Exposure Levels (RELs).  The Surveillance Program has conducted two nationwide surveys of work sites and some of its findings are cited here.

a. NIOSH Recommended Exposure Level (REL)

This section indicates that a NIOSH recommendation for occupational exposure has been published.  The RELs may appear in any of several document forms: Criteria Documents, Current Intelligence Bulletins, Special Hazard Reviews, Occupational Hazard Assessments, and Technical Guidelines.  NIOSH also periodically presents testimony before various Congressional committees and at regulatory hearings convened by OSHA and MSHA.  The testimony presented always includes the current NIOSH policy concerning the particular hazard in question.  A summary of NIOSH recommendations is contained in DHHS (NIOSH) Publication 92-100.

b. NIOSH Occupational Exposure Survey data

NIOSH Survey Data (NOHS [National Occupational Hazard Survey], 1974, or NOES [National Occupational Exposure Survey], 1983) indicate that information on potential occupational exposure to the substance exist in one or both of the databases assembled as a result of national surveys of industry in the United States.  The first survey, the NOHS, was conducted from February 1972 to June 1974; the second, the NOES from November 1980 to May 1983.  The intent of both surveys was to associate potential exposure agents (chemical, physical, and biological) with industry types, occupations, and specific surveyed facilities.

In both surveys, the sample of surveyed facilities was designed to permit projections to the national level based on survey results.  It is possible, for example, to estimate the total number of people potentially exposed to a particular agent.  Among other data reporting capabilities of each survey are the actual number of industries, occupations, or facilities in which an agent was observed.

There are several limitations, dictating the need for caution and some reservations, that must be observed in the interpretation and any subsequent use of the occupational exposure data presented in this field.

 - The occupational exposure data presented for each survey were representative of the workplace at the respective times each survey was conducted.  The data are becoming progressively more dated, and as a consequence, less representative of the current situation.

 - Data in both surveys were collected using observational techniques.  No environmental levels of chemical or biological contaminants or degrees of physical hazards were actually measured.

 - Neither survey covered industries in mining or agriculture.  The sample universe of the NOHS did not include rural areas.  The NOES did not include Federal, State, or local governments, financial, real estate, or retail trade industries.

 - Exposure data reported for both surveys are provisional.  In both cases, the majority of exposure data (approximately 70%) recorded during both surveys was by trade name product.  Subsequent detailed component information for these trade name products was sought from the manufacturers and incorporated into the respective survey databases.

Basic Parameters of both surveys are as follows:

Here is the survey data for benzene.  Types of data and the abbreviations used in the text appear below:

NOHS 1974: HZD 09070; NIS 126; TNF 11184; NOS 106; TNE 147583;
NOES 1983: HZD 09070; NIS 92; TNF 10054; NOS 117; TNE 272275; TFE 143066

HAZARD CODE (HZD) - a five-position identifier used exclusively by NIOSH for search and retrieval of data from either survey database.

NUMBER OF INDUSTRIES (NIS) - number of industries, as defined by standard 4-digit industrial classification (SIC) codes, in which the agent was observed.

TOTAL NUMBER OF FACILITIES (TNF) -estimated (nationwide) total number of facilities in which the agent is thought to be present.

NUMBER OF OCCUPATIONS (NOS) - number of occupations, as defined by the Bureau of Census Occupational codes, in which the agent was observed.

TOTAL NUMBER OF EMPLOYEES (TNE) - estimated (nationwide) total number of employees thought to be exposed to the agent.

TOTAL NUMBER OF FEMALE EMPLOYEES (TFE) - estimated (nationwide) total number of female employees thought to be exposed to the agent (available for the NOES only).

Questions specific to the occupational survey data reported in the Registry should be directed to:

NIOSH
Surveillance Branch, Hazard Section
Mail Stop R-19
4676 Columbia Parkway
Cincinnati, Ohio 45226
FAX: (513) 841-4489

Detailed descriptions of the surveys and their resulting databases are available in the following NIOSH technical reports:

The search example given above will retrieve all the records in RTECS containing NOES data.

This is one of the fields created from the original RTECS Acute Toxicity data which permits comparison of integer-based LD50 values (ng/kg) for this route-species combination.  In order to provide such a retrieval capability it has been necessary to scale and normalise the values.  Nevertheless, where this field occurs, it is accompanied by the same value in mg/kg in square brackets together with the applicable Toxic Effect Codes.  For example, for Acetic acid, fluoro, sodium salt, February 2001, data the contents of the IHNG field were:

100000 ng/kg. [0.100000 mg/kg] T/E unlistd

Please note that only the first integer displayed is indexed.

If ever a value is too large for the SPIRS search engine to handle a value of 999999999999 appears (although the true value appears within square brackets).  The search example given above finds those LD50 values for oral-rat which are less than or equal to 0.1 mg/kg.  In the construction of this field, indeterminate values (i.e. LD50 > ...) are ignored.  Please also note that in selecting such data, MDL always selects the lowest available from the literature.

Looking at the field-specific limit index for the ORNG field will quickly reveal the most lethal substances in this context (lowest LD50 values).

For more general information about LD50 values click here.

This is one of the fields created from the original RTECS Acute Toxicity data which permits comparison of integer-based LD50 values (nL/kg) for this route-species combination.  In order to provide such a retrieval capability it has been necessary to scale and normalise the values.  Nevertheless, where this field occurs, it is accompanied by the same value in mL/kg in square brackets together with the applicable Toxic Effect Codes.  For example, for Acetic acid, ((trimethylstannyl)thio)-, isooctyl ester, February 2001 data, the contents of the ORNL field were:

20000 nL/kg. [0.020000 mL/kg] F07-K12-M30

Please note that only the first integer displayed is indexed.

If ever a value is too large for the SPIRS search engine to handle a value of 999999999999 appears (although the true value appears within square brackets).  The search example given above finds those LD50 values for oral-rat which are less than or equal to 0.02 mL/kg.  In the construction of this field, indeterminate values (i.e. LD50 > ...) are ignored.  Please also note that in selecting such data, MDL always selects the lowest available from the literature.

Looking at the field-specific limit index for the ORNL field will quickly reveal the most lethal substances in this context (lowest LD50 values).

For more general information about LD50 values click here.

RTECS includes two fields for substance names.  This field contains a single, common, generally recognized name of the chemical.  The Synonyms (SY) field contains additional chemical, generic, trivial or trade name(s) of the substance.  Each of these fields can be searched individually but in general it is best to use the combination Name Fragments header (ZNF) to search both fields SIMULTANEOUSLY because the name you use may not be the CHRIS name selected for the record.

The prime name of each substance is derived from the nomenclature used by the American Chemical Society's Chemical Abstracts Service (CAS) in the Collective Index of Chemical Abstracts.  Sometimes the specific collective index from which the name is extracted is cited (e.g. 8CI, 9CI etc.).  Names are in inverted form.  Names are modified by MDL for some substances for user convenience in grouping substances of similar occupational pertinence, such as metallic salts.  Some records use chemical or descriptive names from the reference from which toxic data were obtained, particularly when some aspects of the substance's composition are in question, such as plant or animal extracts.  These records also have a CD field providing more descriptive information concerning the substance.

In many cases names have been hyphenated.  That is to say that all space characters in the name have been changed to hyphens and a terminal hyphen added.  Where this occurs and given the way SPIRS works, this means that the whole name appears in the index in hyphenated form together with each individual term making up the word.  The hyphenation and terminal hyphen acts as a device to indicate that the term does indeed come from the prime name or synonym field as opposed to other free text fields where the name will not, in general, be hyphenated in this way.  There is another important reason for adding a terminal hyphen - to aid focussed retrieval.  For example, the search benzene- in pn retrieves only the one record for the substance benzene, while benzene in pn retrieves all records containing the word 'benzene' in the PN field.  Similarly, acetic-acid- in pn retrieves only the single record for acetic acid, while acetic acid in pn retrieves any record with those two words adjacent to each other in the PN field.  Whilst this device does not always work, it will always reduce the number of irrelevant records retrieved, in some cases dramatically.

As a general rule, hyphenation is not attempted in names which contain 'natural breaks' (such as parentheses, curly braces, brackets, slash characters etc.) or characters other than alphanumerics, commas, hyphens or spaces or names which are over 90 characters long.

Each word that appears in the PN field is searchable separately.  All parts of common and chemical names, including parent, substituents, modifiers, and locants are individually or collectively searchable, as in the above examples.

It is strongly recommended that you employ the technique of lateral searching when searching for long, complex names or parts of names from the records display area or free text index OR enclose the name or part-name in quotation marks.  See the section on indexable characters and searching for more useful information.

This field occurs in every RTECS record.

Please refer to the synonym(s) for closely related and additional information.

This is one of the fields contained within the Citation list (CITN).

Each reproductive effects data segment includes, in sequence, the reproductive effects code(s), the route of exposure, the species of animal tested, the type of dose, the total dose amount administered, the time and duration of administration, and the reference from which the information was extracted.  Only positive reproductive effects data for mammalian species are cited in the Registry.  Because of differences in the reproductive systems among species and the systems' varying responses to chemical exposures, no attempt is made to extrapolate animal data or to evaluate the significance of a substance as a reproductive risk to humans.  Here is an example of a data segment.  More than one segment can appear in the field.

T12-T13-T14 unr-grb TDLo: 375 mg/kg (25D pre)
 - Indian Journal of Experimental Biology.  (Publications & Information
 - Directorate, CSIR, Hillside Rd., New Delhi 110 012, India)
 - V.1-  1963-  16,984,1978 (IJEBA6)

Each element of the reproductive effects data segment is discussed below:

a. Reproductive Effects Code

For purposes of the Registry, the reproductive effects for which dose data are cited have been grouped into seven categories: paternal effects, maternal effects, effects on fertility, effects on the embryo or fetus, specific developmental abnormalities, tumorigenic effects, and effects on the newborn.  Within these seven categories, 65 specific effects have been defined.  The effects cited in a given data segment were reported to occur in the species and at the dose level given on that line.  Up to three reproductive effects are cited on a single data segment.  If more than three reproductive effects are reported for the same route-species-dose level-duration combination, duplicate entries will appear in this field to allow complete coding of the reproductive effects.  The reproductive effects codes from the example above are T12-T13-T14 which cover the maternal effects of ovaries, fallopian tubes, uterus, cervix, vagina and menstrual cycle changes or disorders.

b. Route of Exposure or Administration

See the table for a complete list of abbreviations and definitions of the various routes of exposure reported in the Registry.  For reproductive effects data, the specific route is listed in RTECS either when the substance was administered to only one of the parents or when the substance was administered to both parents by the same route.  However, if the substance was administered to each parent by a different route, the route is indicated as "mul" (multiple).  For the example given above the route code is given as 'unr' which is unreported (see the abbreviations section).

c. Species Exposed

Reproductive effects data are cited in the Registry for mammalian species only.  Species abbreviations are the same as those used for acute toxicity data and are shown elsewhere.  Also shown there are approximate gestation periods.

d. Type of Exposure

Only two types of exposure, TDLo and TCLo, are used to describe the dose amounts reported for reproductive effects data.  These two terms, which are also used to describe toxic dose data, are defined in the section for the acute toxicity field.

e. Dose Amounts and Units

The total dose amount that was administered to the exposed parent is given.  If the substance was administered to both parents, the individual amounts to each parent are added together and the total amount shown.  Where necessary, appropriate conversion of dose units is made.  The dose amounts listed are those for which the reported effects are statistically significant.  The statistical test is that used by the author.  If no statistic is reported, a Fisher's Exact Test is applied with significance at the 0.05 level, unless the author makes a strong case for significance at some other level.

Dose units are usually given as an amount administered per unit body weight or as parts of vapor or gas per million parts of air by volume.  A complete description of dose units is given in the section for the acute toxicity field.  There is no limitation on either the quantity or concentration of the dose or the duration of exposure reported to have caused the reproductive effect.

f. Time and Duration of Treatment

The time when a substance is administered to either or both parents may significantly affect the results of a reproductive study, because there are differing critical periods during the reproductive cycles of each species.  Therefore, to provide some indication of when the substance was administered, which should facilitate selection of specific data for analysis by the reader, a series of up to four terms follows the dose amount.  These terms indicate to which parent(s) and at what time the substance was administered.  The terms take the general form:

 - (uD male/vD pre/w-xD preg/yD post)

where u = total number of days of administration to male prior to mating
v = total number of days of administration to female prior to mating
w = first day of administration to pregnant female during gestation
x = last day of administration to pregnant female during gestation
y = total number of days of administration to lactating mother after birth of offspring

If administration is to the male only, then only the first of the above four terms is shown following the total dose to the male, e.g., 10 mg/kg (5D male).  If administration is to the female only, then only the second, third, or fourth term, or any combination thereof, is shown following the total dose to the female.  For example:

 - 10 mg/kg (3D pre)
 - 10 mg/kg (3D pre/4-7D preg)
 - 10 mg/kg (3D pr/4-7D per/5D post)
 - 10 mg/kg (3D pre/5D post)
 - 10 mg/kg (4-7D preg)
 - 10 mg/kg (4-7D preg/5D post)
 - 10 mg/kg (5D post)  (NOTE: This example indicates administration to the lactating mother only after birth of the offspring.)

If the administration is to both parents, then the first term and any combination of the last three terms are listed, e.g., 10 mg/kg (5D male/3D preg/4-7D post).  If administration is continuous through two or more of the above periods, the above format is abbreviated by replacing the slash (/) with a dash (-).  For example, 10 mg/kg (3D pre-5D post) means a total of 10 mg/kg administered to the female for three days prior to mating, on each day during gestation, and for five days following birth.

g. Multigeneration Studies

Some reproductive studies entail administration of a substance to several consecutive generations, with the reproductive effects measured in the final generation.  The protocols for such studies vary widely.  Therefore, because of the inherent complexity and variability of these studies, they are cited in RTECS in a simplified format as follows:

The specific route of administration is reported if it was the same for all parents of all generations; otherwise, the abbreviation "mul" is used.  The total dose amount shown is that administered to the F0 generation only (as described in e. above); doses to the Fn (where n = 1,2,3, etc.) generations are not reported.  The time and duration of treatment for multigeneration studies are not included in the data segment.  Instead, the dose amount is followed by multigeneration, e.g., 10 mg/kg multigeneration.  The reader must consult the cited reference for complete details of the study protocol.

This field does NOT exist in the original RTECS data but has been created in this Croner implementation as an aid for users.  It allows the retrieval of either new OR modified or reviewed OR existing records when compared with the last Croner update.  These three possibilities are mutually exclusive and appear in records as:

E Existing-record

or

M Modified-or-reviewed-record

or

N New-record

Searching can thus be confined to just newly added chemical records as in the second search example given above which retrieves all new records containing oral rat LD50 information.

The first search example returns those records which have been modified or reviewed since the last Croner update.

This is one of the fields contained within the Citation list (CITN).

The CAS Registry number is a numeric designation assigned by the Chemical Abstracts Service of the American Chemical Society that uniquely identifies a specific chemical compound, regardless of the name or nomenclature system used.

Because CAS, on occasion, assigns new numbers to selected chemicals without withdrawing the previously assigned numbers, confusion sometimes arises.  This situation occurs when a substance is better described or more accurately identified.  The former RTECS policy of listing only the current CAS number for a substance and dropping the earlier number with its periodic updates has resulted in the loss of previously accepted CAS numbers accessed by users of the database.  Therefore, RTECS will list the most recent CAS number available for a chemical and, to preserve continuity and prevent confusion, will include a second CAS number line which will list "Previous" CAS numbers.  Up to ten (10) such previous CAS numbers will be listed for a substance.

The number is always expressed in a hyphenated format with any leading zeroes omitted.  When searching in the RN field, include the hyphens; truncation and wildcards can be used as well (see the first search above) as sometimes similar CAS numbers refer to similar chemicals.  You can also omit the field label as the data is also now indexed as free text.

Using the CAS number is one of the fastest ways to get to a particular record.  CAS numbers exist in over 80% of RTECS records.

This is one of the fields contained within the Citation list (CITN).

This is one of the fields created from the original RTECS Acute Toxicity data which permits comparison of integer-based LD50 values (ng/kg) for this route-species combination.  In order to provide such a retrieval capability it has been necessary to scale and normalise the values.  Nevertheless, where this field occurs, it is accompanied by the same value in mg/kg in square brackets together with the applicable Toxic Effect Codes.  For example, for Triethylamine, 2,2',2''-trichloro-, February 2001 data, the contents of the SKNG field were:

2000000 ng/kg. [2.000000 mg/kg] T/E unlistd

Please note that only the first integer displayed is indexed.

If ever a value is too large for the SPIRS search engine to handle a value of 999999999999 appears (although the true value appears within square brackets).  The search example given above finds those LD50 values fopr skin-rat which are less than 3 mg/kg.  In the construction of this field, indeterminate values (i.e. LD50 > ...) are ignored.  Please also note that in selecting such data, MDL always selects the lowest available from the literature.

Looking at the field-specific limit index for the SKNG field will quickly reveal the most lethal substances in this context (lowest LD50 values).

For more general information about LD50 values click here.

This is one of the fields created from the original RTECS Acute Toxicity data which permits comparison of integer-based LD50 values (nL/kg) for this route-species combination.  In order to provide such a retrieval capability it has been necessary to scale and normalise the values.  Nevertheless, where this field occurs, it is accompanied by the same value in mL/kg in square brackets together with the applicable Toxic Effect Codes.  For example, for Benzoic acid, benzyl ester, February 2001 data, the contents of the SKNL field were:

4000000 nL/kg. [4.000000 mL/kg] T/E unlistd

Please note that only the first integer displayed is indexed.

If ever a value is too large for the SPIRS search engine to handle a value of 999999999999 appears (although the true value appears within square brackets).  The search example given above finds those LD50 values for skin-rat which are less than 5 mL/kg.  In the construction of this field, indeterminate values (i.e. LD50 > ...) are ignored.  Please also note that in selecting such data, MDL always selects the lowest available from the literature.

Looking at the field-specific limit index for the SKNL field will quickly reveal the most lethal substances in this context (lowest LD50 values).

For more general information about LD50 values click here.

This field provides information on the activities of various governmental agencies regarding the substance.  Status lines are currently listed for ATSDR, EPA, NIOSH, NTP, and OSHA.

a. ATSDR

The Agency for Toxic Substances and Disease Registry (ATSDR) has been directed by the Superfund Amendments and Reauthorization Act of 1986 (SARA) to prepare toxicological profiles for hazardous substances that pose the most significant potential threat to human health, as determined by ATSDR and the Environmental Protection Agency (EPA).  Each profile is intended to characterize the toxicological and adverse health effects information for the hazardous substance being described.  The currently available profiles are noted in the Status field of the appropriate chemical records.  Also noted is the NTIS Stock Number of each profile.

b. EPA

EPA status entries are included for five portions of the Toxic Substances Control Act (TCSA), Public Law 94-469: Section 8(a) preliminary assessment information, Section 8(b) chemical inventory, Section 8(d) Health and safety studies, and Section 8(e) substantial risk information, and TSCA Test Submissions Database (TSCATS).  Additional status lines are listed for two other EPA programs: GENE-TOX and IRIS.

A TSCA inventory reference indicates that the substance appears on the Chemical Inventory prepared in 1986 by the EPA in accordance with provisions of Section 8(b) of TSCA.  Substances reported in the inventory include those that are produced commercially in or imported into the USA.  The reader should note, however, that substances already regulated by EPA under FIFRA and by the Food and Drug Administration (FDA) under the Food, Drug, and Cosmetic Act, as amended, are not included in the TSCA inventory.  Similarly, alcohol, tobacco, and explosive substances are not regulated under TSCA.  TSCA regulations should be consulted for an exact definition of reporting requirements.  Approximately seven percent of the RTECS chemicals are contained in the TSCA inventory.

A preliminary assessment information status line indicates that EPA has promulgated both a final and a proposed rule under Section 8(a) of TSCA, reporting and retention of information.  The final rule requires chemical manufacturers and, in some cases, processors and importers to report production and exposure-related data on approximately 250 chemicals to EPA.  Included in this status line is a reference to the Federal Register issue (volume 47, page 26992, June 22, 1982) in which the rule appeared.  This reference should be consulted for a complete explanation of the rule.  The proposed rule (Federal Register, volume 47, page 27009, June 22, 1982) covered an additional 350 chemicals for which similar reporting would be required.

Under TSCA Section 8(d), manufacturers, importers, and/or processors of a substance specified by the EPA Administrator must submit lists and copies of unpublished health and safety studies on that substance.  Specified substances include chemical substances that are selected for consideration for testing rules under TSCA section 4, as well as other chemicals that EPA had identified as of concern under TSCA.  A "health and safety" study is interpreted broadly and may include not only formal studies but also other types of information relating to health and environmental effects, including relevant monitoring and exposure data.

A substantial risk status line indicates that EPA has received and reviewed information submitted under Section 8(e) of TSCA, which requires that persons who obtain information which reasonably supports the conclusion that a substance presents substantial risk of injury to human health or the environment must notify EPA within 15 days.  These notices are reviewed by EPA and an initial evaluation is prepared containing, if appropriate, follow-up questions to the submitter, referrals to other agencies, and decisions to list the chemical for a Section 8 reporting rule or to undertake a formal risk assessment.  The submissions and the initial evaluations are in the Public Reading Room, 447 East Tower, Waterside Mall, 401 M Street, SW, Washington, D.C. 20460.  Persons wishing to request a copy of these notices may write to the EPA Freedom of Information Office (A-101), Washington, D.C. 20460.  A duplication fee will be charged.  The reader should note that many 8(e) notices represent a company's first review of a situation or datum and a judgment in compliance with the statute to submit a notice within 15 days of obtaining the information.  EPA published its evaluations of these notices in order to make widely available this Section 8(e) information in a form understandable to the general public.

The TSCATS (TSCA Test Submissions) was developed to make unpublished test data submitted to EPA available to the public.  Test is broadly defined to include case reports, episodic incidents (such as spills), and formal test study presentations.  The database (except for the microfiche version) allows searching of test submissions according to specific chemical identity or type of study.  Studies are indexed under three broad subject areas: health effects, environmental effects, and environmental fate.  Additional controlled vocabulary index terms are assigned that describe the experimental protocol and test observations.  Records identify reference information needed to locate the source document, as well as the submitting organization and reason for submission of the test data.  The first search example given above finds all those EPA status lines involving TSCATS.

GENE-TOX:  A Genetic Toxicology program status line indicates that the substance has been reported in the literature for potential genetic effects.  The test protocol in the literature is evaluated by an EPA Expert Panel on Mutations and a positive or negative effect of the substance is evaluated and reported.  To obtain additional information about this program, contact GENE-TOX Program, EPA, 401 M Street SW, TS796, Washington, D.C. 20460, telephone (202) 260-1513.

IRIS:  The Integrated Risk Information System is the EPA electronic on-line database of summary health risk assessment and regulatory information on chemical substances.  The primary purpose of IRIS is to provide guidance risk values to EPA risk assessors and decision makers for use in EPA risk management decisions.  EPA staff and EPA contractors are expected to use the risk information in IRIS for those chemicals in the database.  The information contained in IRIS, except as specifically noted, has been reviewed and agreed upon by intra-agency review groups comprised of EPA scientists, having extensive experience in risk assessment.  Thus, the information in IRIS represents an expert Agency consensus.  The third search example given above finds all the IRIS references in RTECS.

c. NIOSH

NIOSH data segments are included for those substances for which an analytical method(s) has been developed by NIOSH or for substances for which NIOSH Current Intelligence Bulletins (CIBs) have been issued.  The chemicals listed in the Fourth Edition of the "NIOSH Manual of Analytical Methods (NMAM)" are also cited in the RTECS.  The sampling and measurement methods in the NMAM Fourth Edition are revisions and additions to those contained in the previous editions.

d. National Toxicology Program (NTP)

Toxicology status lines listed in the RTECS file indicate that the substance has been or is being tested by the NTP under its Carcinogenesis Testing Program.  These entries were identified as National Cancer Institute (NCI) status lines in issues of the Registry prior to July 1980.  However, the NCI Carcinogenesis Testing Program has been absorbed by NTP, and the status lines have been reformatted accordingly.  The following different references are used to reflect the current test status of the compound:  nominated for test; selected for test; currently undergoing test; or test completed.

These references are updated as each bioassay progresses.  Selection of a chemical for bioassay does not necessarily imply that it is a carcinogen.  Also, a compound originally selected and even scheduled for bioassay may be withdrawn from the program anytime during testing or before testing actually begins.  This initial selection is cited in the Registry but is deleted when the compound is removed from the test.  It is, therefore, important that the reader monitor these status lines for changes.  The bioassay itself normally takes about two and one half years to conduct, and another year is required to prepare the final report.  When this report is released, the report number and test results are listed, and, where applicable, specific tumorigenic dose data are generated.  In June 1983, NTP adopted five categories of interpretive conclusions for use in their technical reports.  The Registry references make use of these same five categories in the NTP Status Lines.  As defined by NTP, the categories (which refer to the strength of the experimental evidence) are as follows:

 - CLEAR EVIDENCE of carcinogenicity is demonstrated by studies that are interpreted as showing a chemically related increased incidence of malignant neoplasms, studies that exhibit a substantially increased incidence of benign neoplasms, or studies that exhibit an increased incidence of a combination of malignant and benign neoplasms where each increases with dose (see the second search example given above).

 - SOME EVIDENCE of carcinogenicity is demonstrated by studies that are interpreted as showing a chemically related increased incidence of benign neoplasms, studies that exhibit marginal increases in neoplasms of several organs/tissues, or studies that exhibit a slight increase in uncommon malignant or benign neoplasms.

 - EQUIVOCAL EVIDENCE of carcinogenicity is demonstrated by studies that are interpreted as showing a chemically related marginal increase of neoplasms.

 - NO EVIDENCE of carcinogenicity is demonstrated by studies that are interpreted as showing no chemically related increases in malignant or benign neoplasms.

 - INADEQUATE STUDY of carcinogenicity demonstrates that because of major qualitative or quantitative limitations, the studies cannot be interpreted as valid for showing either the presence or absence of a carcinogenic effect.

Final reports for some bioassays may not be published because the data are insufficient, and this is noted in the Registry where applicable.  Also, some substances may be selected by NTP for retest after the first bioassay is completed and the final report issued.  These duplicate studies are noted on a separate NTP status line.  Some of the early NCI testing was not done in accordance with the strict experimental protocols now used.  The results of these studies were not published as NCI bioassay reports, but instead appeared in the literature as journal articles.  These are noted on the NTP status lines as "studies" rather than "bioassays", and reference to the journals are given.  To obtain additional information about the Carcinogenesis Testing Program or the status of a particular substance under test, or to obtain copies of the final bioassay reports, contact the Central Data Management, Mail Drop E1-02, NIEHS, P.O. Box 12233, Research Triangle Park, North Carolina 27709, telephone (919) 541-3991.

The second type of NTP status line indicates that the substance is listed in the "NTP Biennial Report on Carcinogens".  This cumulative list is published in accordance with Public Law 95-622, which requires that the Secretary of Health and Human Services publish a biennial report containing ". . . a list of all substances (i) which either are known to be carcinogens or which may reasonable be anticipated to be carcinogens and (ii) to which a significant number of persons residing in the United States are exposed . . .".  Included for each of the 198 chemicals in the report is a description of the substance, including a brief synopsis of the scientific evidence that led to its inclusion in the report.  This is immediately followed by information about the regulatory activities of the NTP-participating federal agencies.  For additional information about the report, contact the Environmental Health Information Service (EHIS), telephone (919) 541-3841 National Toxicology Program, P.O. Box 12233, Research Triangle Park, North Carolina 27709, telephone (919) 541-3841.  Subsequent NTP reports on Carcinogens will be cited in future updates of the Registry.

e. OSHA

The OSHA data that now appears in RTECS is a notation that a validated analytical method(s) has been developed for the chemical by OSHA and appears in its Manual of Analytical Methods.  The manual, in loose leaf form, can be ordered from the American Conference for Governmental Industrial Hygienists (ACGIH) (513) 742-2020.  OSHA Manual of Analytical Methods: Inorganic Methods (ID-101 to ID-210) publication number 4545; Organic Methods (#1-80) publication number 4542, Organic Methods Supplement (#55-80) publication number 4544.

This field contains notations indicating the substance is regulated by an agency of the United States Government, either by EPA, MSHA, or OSHA, or as Occupational Exposure Limits (OEL) by other nations around the world.  EPA refers to substances regulated by the Federal Insecticide Fungicide, and Rodenticide Act (FIFRA) of the U.S. Environmental Protection Agency.  MSHA refers to standards promulgated by the Mine Safety and Health Administration, under Subpart D, Section 56 of the Federal Mine Safety and Health Act of 1977.  These have been codified in 30CFR 56.0001.  OSHA refers to standards promulgated under Section 6 of the Occupational Safety and Health Act of 1970.  These have been codified in the Code of Federal Regulations (CFR), Part 29, and are referred to as Permissible Exposure Limits (PELs). OEL refers to the Occupational Exposure Limits published by several nations around the world.

All United States standards and regulations are listed in the appropriate Federal Register (FR) or Code of Federal Regulations (CFR) reference.  Because of frequent changes to and litigation of federal regulations, it is recommended that the reader contact the applicable agency for information about the current standards for a particular substance.  Omission of a substance or regulatory notation from the Registry does not imply any relief from regulatory responsibility.

a. EPA FIFRA Standards

These standards indicate pesticides that are subject to registration or reregistration under the Federal Insecticide, Fungicide, and Rodenticide Act, as amended.  The amendments were issued in four parts, representing four lists of pesticides: (a) Federal Register 54(35), page 7740, Feb 22, 1989; (b) Federal Register 54(100), page 22706, March 25, 1989; (c) Federal Register 54(140), page 30848, July 24, 1989; and (d) Federal Register 54(204), page 4388, October 24, 1989.

b. MSHA air contaminants standards

These are noted with the entry "MSHA STANDARD", followed by "air".  The standards for coal mines are defined in Subpart D, Section 56.0001 of 30 CFR as follows: "The exposure to airborne contaminants shall not exceed, on the basis of a time-weighted average, the threshold limit values adopted by the American Conference of Governmental Industrial Hygienists, as set forth and explained in the 1972 edition of the publication, entitled 'TLVs Threshold Limit Values for Chemical Substances in Workroom Air' adopted and published by ACGIH for 1972, pages 1 through 54".  Standards for metal and nonmetal mines were adopted in like manner from the 1973 edition of "TLV Threshold Limit Values for Chemical Substances in Workroom Air".  For those substances where a change in TLV was adopted in 1973, the air contaminant standards for coal mines and for metal and nonmetal mines differ.  Therefore, these RTECS substances will include two lines: (1) MSHA Coal Mine Standard; and (2) MSHA metal and nonmetal mine standard.

c. OSHA air contaminant standards

These are noted by the entry "OSHA PEL" (Permissible Exposure Limit).  These PELs are derived from four sections (tables) of 29CFR.  The four cited sections are:

 - General Industry Standards -- 29CFR 1910.1000, 94
 - Constructions Standards -- 29CFR 1926.55, 94
 - Shipyard Standards -- 29CFR 1915.1000,93 (see the first search example given above)
 - Standards for Federal Contractors -- 41 CFR 50-204.50,94.

The PEL may be further described by one or more of the following terms: "8-hour TWA" (time-weighted average), "STEL" (short term exposure limit) or "CL" (ceiling limit).  The TWA is the employee's airborne exposure in any 8-hour work shift of a 40-hour work week which shall not be exceeded.  The STEL is the employee's 15-minute time-weighted average, which shall not be exceeded at any time during the work day.  A time period other than 15 minutes may be specified in parentheses behind the notation "STEL".  The CL is the employee's exposure, which shall not be exceeded at any time during the work shift.  The notation "(skin)", following the PEL for a substance indicates that even though the air concentration may be below the PEL, significant additional exposure to the skin may be dangerous.  The use of personal protective equipment, engineering controls, or work practices is required.

Some workplace exposures consist of more than one contaminant.  OSHA regulations provide for the reduction of PELs based on additive or synergistic health effects.

OSHA Cancer Hazard and OSHA Suspect Cancer Agent designations may appear on a subsequent data segment for selected substances regulated by OSHA as carcinogens.

The reader is cautioned that some OSHA PELs are promulgated for classes of compounds rather than for individual substances.  These classes may be based on certain chemical or physical properties that have not been well defined for every member of the class.  Any questions about specific OSHA PELs should be directed to:

OSHA
Office of Public Affairs
Room N-3647
Department of Labor
200 Constitution Avenue, NW
Washington, D.C. 20210
Telephone (202) 219-8151.

e. International Occupational Exposure Limits (OELs)

In recent years, RTECS has become widely used around the world.  Therefore, to increase RTECS relevance to the international scientific community (from which its data are drawn), OELs from many nations were acquired, collated, and added to the RTECS in 1993.  These data are continuously updated as new values become available.  The second search example finds all Polish OEL data in RTECS.

This is one of the fields created from the original RTECS Acute Toxicity data which permits comparison of integer-based LD50 values (ng/kg) for this route-species combination.  In order to provide such a retrieval capability it has been necessary to scale and normalise the values.  Nevertheless, where this field occurs, it is accompanied by the same value in mg/kg in square brackets together with the applicable Toxic Effect Codes.  For example, for Dibenzo-p-dioxin, 2,3,7,8-tetrachloro-, February 2001 data, the contents of the SRNG field were:

275000 ng/kg. [0.275000 mg/kg] T/E unlistd

Please note that only the first integer displayed is indexed.

If ever a value is too large for the SPIRS search engine to handle a value of 999999999999 appears (although the true value appears within square brackets).  The search example given above finds those LD50 values for skin-rabbit which are less than 1 mg/kg.  In the construction of this field, indeterminate values (i.e. LD50 > ...) are ignored.  Please also note that in selecting such data, MDL always selects the lowest available from the literature.

Looking at the field-specific limit index for the SRNG field will quickly reveal the most lethal substances in this context (lowest LD50 values).

For more general information about LD50 values click here.

This is one of the fields created from the original RTECS Acute Toxicity data which permits comparison of integer-based LD50 values (nL/kg) for this route-species combination.  In order to provide such a retrieval capability it has been necessary to scale and normalise the values.  Nevertheless, where this field occurs, it is accompanied by the same value in mL/kg in square brackets together with the applicable Toxic Effect Codes.  For example, for Lactonitrile, February 2001 data, the contents of the SRNL field were:

20000 nL/kg. [0.020000 mL/kg] T/E unlistd

Please note that only the first integer displayed is indexed.

If ever a value is too large for the SPIRS search engine to handle a value of 999999999999 appears (although the true value appears within square brackets).  The search example given above finds those LD50 values which are less than 0.02 mL/kg.  In the construction of this field, indeterminate values (i.e. LD50 > ...) are ignored.  Please also note that in selecting such data, MDL always selects the lowest available from the literature.

Looking at the field-specific limit index for the SRNL field will quickly reveal the most lethal substances in this context (lowest LD50 values).

For more general information about LD50 values click here.

Synonyms (which are listed in alphabetical order) include other chemical names, trade names, common or general names, foreign language names (with the language in parentheses), or codes.  Some synonyms consist wholly or in part of registered trademarks.  These trademarks are not identified as such in the RTECS file because of limitations in the computer character sets used to produce the Registry.  The Editor is aware of the problem of trademarks becoming generic trade names through common usage.  While the Registry does not presently have a mechanism for noting trademarks, the lack of the appropriate registered trademark symbol does not imply that the trademarks contained herein are considered generic synonyms by MDL.  Those trade names that are known to be obsolete, either because production and marketing of the substance has ceased or because the compound is currently manufactured under another name, are indicated with the abbreviation "(Obs)".

Some synonyms, particularly common names, may be ambiguous and refer to multiple substances which may or may not be chemically similar.  The RTECS list of synonyms is not exhaustive, and may not include every existing use of a particular common name.  Therefore, when using a synonym in searching, make sure that you have retrieved the correct substance record.  In general it is best to use the Name Fragments field (ZNF) to search both this and the Prime Name field (PN) SIMULTANEOUSLY because the name you use may not be the RTECS name selected for the record.

Note that hyphenation is performed in exactly the same way as for RTECS Prime Name (PN).

It is strongly recommended that you employ the technique of lateral searching when searching for long, complex names or parts of names from the records display area or free text index OR enclose the name or part-name in quotation marks, as shown in the third search example above.  See the section on indexable characters and searching for more useful information.

This is one of the fields contained within the Citation list (CITN).

Tumorigenic dose data also appear in the reproductive effects field.  The format of these data types are identical to that of the acute toxicity field.

Briefly, each tumorigenic data segment sequentially includes toxic effects code(s), the route of exposure, the species of animal studied, the type of dose (either TDLo or TCLo), the total dose amount administered, the duration of exposure, and the reference from which the information was extracted.  Only positive or equivocal tumorigenic reports are cited in this field.  For other information about tumorigenicity, the reader should see the IARC and ACGIH monograph data  in the toxicology/cancer reviews field and the NTP status data.

The importance attached to reports of the carcinogenic activity of substances necessitates a more detailed discussion of the criteria used to include this type of data in the Registry.  Tumorigenic references are coded according to the reported results of the study only to aid the reader in selecting appropriate references for in-depth review and evaluation.  The two codes used are V01, indicating a positive carcinogenic finding, and V02, indicating a study producing benign tumors.  A third code, V03, was added to denote those studies reporting uncertain, but seemingly positive, results.  The criteria for these three codings are listed below.  As explained in the Introduction, these criteria are used to abstract the data in individual reports on a consistent basis and do not represent a comprehensive evaluation of the tumorigenic potential of a substance to humans.

Because of the increasing concern with carcinogens in the occupational environment, the Registry cites multiple studies in which tumorigenic responses were reported.  That is, for a given substance, a particular route-species combination may be cited more than once if the results of the multiple studies are coded V01, V02, or V03.  These multiple tumorigenic entries have been cited simply with a toxicity measure of TD (toxic dose) or TC (toxic concentration).

The following nine technical criteria are used by RTECS to abstract the toxicological literature and classify studies that report positive tumorigenic responses.  NO ATTEMPTS ARE MADE EITHER TO EVALUATE THE VARIOUS TEST PROCEDURES OR TO CORRELATE RESULTS FROM DIFFERENT EXPERIMENTS.

(a) A reference is coded with the TEC "V01" (carcinogenic) when review of an article reveals that all of the following criteria are satisfied:

 - A statistically significant increase in the incidence of tumors in the test animals.  The statistical test is that used by the author.  If no statistic is reported, a Fisher's Exact Test is applied with significance at the 0.05 level, unless the author makes a strong case for significance at some other level.

 - A control group of animals is used and the treated and control animals are maintained under identical conditions.

 - The sole experimental variable between the groups is the administration or non-administration of the test substance (see (i) below).

 - The tumors consist of autonomous populations of cells of abnormal cytology capable of invading and destroying normal tissues, or the tumors metastasize as confirmed by histopathology.

(b) A reference is coded with the TEC "V02" (neoplastic) when review of an article reveals that all of the following criteria are satisfied:

 - A statistically significant increase in the incidence of tumors in the test animals.  The statistical test is that used by the author.  If no statistic is reported, a Fisher's Exact Test is applied with significance at the 0.05 level, unless the author makes a strong case for significance at some other level.

 - A control group of animals is used, and the treated and control animals are maintained under identical conditions.

 - The sole experimental variable between the groups is the administration or non-administration of the test substance (see (i) below).

 - The tumors consist of cells that closely resemble the tissue of origin, that are not grossly abnormal cytologically, that may compress surrounding tissues, but that neither invade tissues nor metastasize; or

 - The tumors produced cannot definitely be classified as either benign or malignant.

(c) A reference is coded with the TEC "V03" (equivocal tumorigenic agent) when some evidence of tumorigenic activity is presented, but one or more of the criteria listed in (1) or (2) above is lacking.  Thus, a report with positive pathological findings, but with no mention of control animals, is coded V03.  Reports in which the results are not interpretable are not cited in the Registry.

(d) Since an author may make statements or conclusions based on a larger context than that of the particular data reported, papers in which the author's conclusions differ substantially from the evidence presented in the paper are subject to review by the RTECS Editor.

(e) All doses except for those for transplacental carcinogenesis are reported in RTECS in one of the following formats:

 - For all routes of administration other than inhalation: cumulative dose in mg (or other appropriate unit)/kg/duration of administration.

Whenever the dose reported in the reference is not in the above units, conversion to this format is made based on the information given in the acute toxicity data field.  The total cumulative dose is derived from the lowest dose level that produces tumors in the test group.

 - For inhalation experiments: concentrations in ppm (or mg/m3)/total duration of exposure.  The concentration refers to the lowest concentration that produces tumors.

(f) Transplacental carcinogenic doses are reported in RTECS in one of the following formats:

 - For all routes of administration other than inhalation: cumulative dose in mg/kg/(time of administration during pregnancy).  The cumulative dose is derived from the lowest single dose that produces tumors in the offspring.  The chemical is administered to the mother.

 - For inhalation experiments: concentration in ppm (or mg/m3)/(time of exposure during pregnancy).  The concentration refers to the lowest concentration that produces tumors in the offspring.  The mother is exposed to the chemical either during pregnancy or lactation.

(g) For the purposes of RTECS, all test chemicals are reported as pure, unless otherwise stated by the author.  This does not rule out the possibility that unknown impurities may have been present.

(h) A mixture of compounds whose test results satisfy the criteria in (a), (b), or (c) above is included if the composition of the mixture can be clearly defined.

(i) For tests involving promoters or initiators, a study is included if the following conditions are satisfied (in addition to the criteria in (a), (b), or (c) above):

 - The test chemical is applied first followed by an application of a standard promoter.  A positive control group in which the test animals are subjected to the same standard promoter under identical conditions is maintained throughout the duration of the experiment.  The data are not used if no mention of positive and negative control groups is made in the reference.

 - A known carcinogen is first applied as an initiator, followed by application of the test chemical as a promoter.  A positive control group in which the test animals are subjected to the same initiator under identical conditions is maintained throughout the duration of the experiment.  The data are not used if no mention of positive and negative control groups is made in the reference.

Three types of reviews are listed in this field which are :

 - (1) Threshold Limit Values (TLVs), which recommend limits proposed by the American Conference of Governmental Industrial Hygienists (ACGIH);
 - (2) International Agency for Research on Cancer (IARC) monograph reviews, which are published by the United Nations World Health Organization (WHO); and
 - (3) general toxicology review articles.

a. Threshold Limit Value (TLV)

The TLV is an ACGIH-recommended concentration of a substance to which most workers can be exposed without adverse effect.  The TLV may be expressed as a time-weighted average (TWA), as a short term exposure limit (STEL), or as a ceiling value (CL).  The TWA is for a normal 8-hour workday or 40-hour work week.  The STEL is the maximum concentration to which workers can be exposed for up to 15 minutes, provided no more than four excursions per day are permitted with at least 60 minutes between exposure periods and provided the daily TWA is not also exceeded.  The CL is the concentration that should not be exceeded even instantaneously.  The notation "(skin)" indicates that even though the air concentration may be below the limit value, significant additional exposure to the skin may be dangerous.

A separate TLV review line is included for those substances that ACGIH has classified as human carcinogens (either with or without an assigned TLV) or suspected carcinogens.

The TLVs are taken from the "DOCUMENTATION OF THE THRESHOLD LIMIT VALUES FOR SUBSTANCES IN WORKROOM AIR" (sixth edition, 1990 and subsequent annual editions).  Copies of the complete TLV Documentation may be ordered from:

ACGIH
1330 Kemper Meadow Drive
Cincinnati, Ohio  45240
Telephone (513) 742-2020, FAX (513) 742-3355.

The reader is advised that the TLVs are revised periodically.  A "Notice of Intended Changes" for substances for which either a TLV is proposed for the first time or for which a change to an existing TLV is proposed is published annually by ACGIH.  Proposed changes are considered trial limits for two years, after which they are considered for inclusion as adopted TLVs.  Only substances for which TLVs have been adopted and final documentation prepared are cited in the Registry.

In addition, some TLVs are recommended for classes of substances rather than for individual compounds.  These classes may be based on certain chemical or physical properties, such as solubility, that have not been determined for all potential members of the class.  This makes it difficult to cite individual substances belonging to the class.  Any questions about the TLV references in the Registry should be directed to ACGIH.  Any errors should be brought to the attention of the RTECS Editor.

b. IARC Cancer Reviews

In the United Nations International Agency for Research on Cancer (IARC) monographs, information on suspected environmental carcinogens is examined, and summaries of available data with appropriate references are presented.  Included in these reviews are synonyms, physical and chemical properties, uses and occurrence, and biological data relevant to the evaluation of carcinogenic risk to humans.  The 66 monographs in the series contain an evaluation of approximately 1,000 substances.  Single copies of the individual monographs (specify volume number) can be ordered from:

WHO Publications Centre, U.S.A.,
49 Sheridan Avenue,
Albany,
New York 12210,
telephone (518) 436-9686.

The entry "IARC CANCER REVIEW" indicates that some carcinogenicity data pertaining to a compound has been reviewed by the IARC committee.  The Registry summarizes the committee’s conclusion in three words.  The first indicates whether the data pertains to humans or to animals.  The next two words indicate the degree of carcinogenic risk as defined by IARC.

The evidence of carcinogenicity in experimental animals is assessed by IARC and judged to fall into one of four groups defined as follows:

 - SUFFICIENT EVIDENCE of carcinogenicity is provided when there is an increased incidence of malignant tumors: (1) in multiple species or strains; or (2) in multiple experiments (preferably with different routes of administration or using different dose levels); or (3) to an unusual degree with regard to the incidence, site or type of tumor, or age at onset.  Additional evidence may be provided by data on dose-response effects.

 - LIMITED EVIDENCE of carcinogenicity is available when the data suggest a carcinogenic effect but are limited because (1) the studies involve a single species, strain, or experiment; (2) the experiments are restricted by inadequate dosage levels, inadequate duration of exposure to the agent, inadequate period of follow-up, poor survival, too few animals, or inadequate reporting; or (3) the neoplasms produced often occur spontaneously and, in the past,  have been difficult to classify as malignant by histological criteria alone (e.g., lung adenomas and adenocarcinomas, and liver tumors in certain strains of mice).

 - INADEQUATE EVIDENCE is available when, because of major qualitative or quantitative limitations, the studies cannot be interpreted as showing either the presence or absence of a carcinogenic effect.

 - NO EVIDENCE applies when several adequate studies are available which show that within the limitations of the tests used, the chemical is not carcinogenic.

It should be noted that the categories SUFFICIENT EVIDENCE and LIMITED EVIDENCE refer only to the strength of the experimental evidence that these chemicals are carcinogenic and not to the extent of their carcinogenic activity, nor to the mechanism involved.  The classification of any chemical may change as new information becomes available.

The evidence for carcinogenicity from studies in humans is assessed by the IARC committee and judged to fall into one of four groups defined as follows:

 - SUFFICIENT EVIDENCE (see the first search example given above) of carcinogenicity indicates that there is a causal relationship between the exposure and human cancer.

 - LIMITED EVIDENCE of carcinogenicity indicates that a causal relationship is credible, but that alternative explanations, such as chance, bias, or confounding, could not adequately be excluded.

 - INADEQUATE EVIDENCE, which applies to both positive and negative evidence, indicated that one of two conditions prevailed: (a) there are few pertinent data; or (b) the available studies, while showing evidence of association, do not exclude chance, bias, or confounding.

 - NO EVIDENCE applies when several adequate studies are available which do not show evidence of carcinogenicity.

IARC has also published, as Supplement 7, a volume entitled "Overall Evaluation of Carcinogenicity: An Updating of IARC Monographs Volumes 1 to 42".  In this Supplement, and in monographs 43 onward, chemicals have been classified in the following groups:

Group 1 -- The Working Group concluded that the listed agents are carcinogenic to humans.
Group 2A -- The Working Group concluded that the listed agents are probably carcinogenic to humans.
Group 2B -- The Working Group concluded that the listed agents are possibly carcinogenic to humans.
Group 3 -- The Working Group concluded that the listed agents are not classifiable as to their carcinogenicity to humans.
Group 4 -- The Working Group concluded that the listed agent is probably not
carcinogenic to humans.

For any chemical listed in RTECS which appears in one of these groups, its group designation is noted in the Review field, immediately following the IARC Monograph lines.

These cancer reviews reflect only the conclusions of the IARC committees based on the data available for the committee's evaluation.  Hence, for some substances there may be disagreement between the IARC determination and the information on the tumorigenic effects field.  Also, some substances previously reviewed by IARC may be reexamined as additional data become available.  These substances will contain multiple IARC review lines, each of which is referenced to the appropriate IARC volume.

c. Toxicology Reviews.

The entry "TOXICOLOGY REVIEW" (see the second search example given above) indicates that the cited review article has been located in the literature.  Each review is identified by its CODEN reference.  These articles discuss one or more facets of the toxicology of the substance or the general class to which the substance belongs.  Most of these references do not contain specific dose value that can be cited in the Registry.  However, the reviews do provide useful information about the toxicity of the substance or group of related substances.  The reader is cautioned that the scope of discussion varies greatly among the reviews.

Some articles may contain a complete, detailed description of the toxicity of a substance; others may address only a particular aspect of the toxicity (e.g., effect of a substance on fetal development, or body fluid and tissue levels of a substance found under conditions of poisoning); and others may only list the substance in a general discussion of the toxicity of a class of compounds.

This field specifies when the data record of a substance was last changed.  The format is YYYYMM, e.g., 198105 = May 1981.  All 33,929 substances in the file as of January 1979 were initialized with a date of 197901.  When data on a new substance are first input to the file, the update field is assigned the month of entry.  When the data record is subsequently revised, the date is changed to reflect the month the change was made.  Any revision, for example, deletion of an invalid synonym, addition of new acute toxicity data, change in the NTP status, or correction of a molecular formula, will cause this field to change.

This field is particularly useful to limit searches to new data between updates.  The second search example retrieves all those records that have changed since and including November 1997.

You can search the UD field with the following operators, as well as with in and =:

This is one of the fields contained within the Citation list (CITN).

The Wiswesser Line Notation is a line-formula chemical notation that precisely and concisely describes the structural formula of a chemical compound.  This linear representation for a three-dimensional structure facilitates substructure searching for special functional groups and constituents that are part of the molecule.  The WLNs allow machine retrieval by chemical characteristics.

The ZLDC (pseudo-)field combines the following fields so that you can show, download, email or print them simultaneously:

Please note that although the units used for these fields are similar, they are NOT the same.  Click here for more general information regarding this set of fields.

The ZNF (pseudo-)field combines the following fields so that you can search, show, download, email or print them simultaneously:

Prime Name of Substance  (PN)
Synonym(s)  (SY)

This is particularly useful for searching as it may not be known beforehand whether the name selected is a Prime Name or Synonym.  The second search example given above is equivalent to the first and yields exactly the same results.

The Citation is a subset of fields consisting of the following fields:

RTECS Accession Number  (AN)
Record Status  (REC)
Prime Name of Substance  (PN)
CAS Registry Number  (RN)
Beilstein Registry Number  (BRN)
Beilstein Handbook Reference  (BHR)
Update Code  (UD)
Molecular Formula  (MF)
Molecular Weight  (MW)
Synonym(s)  (SY)

The Citation serves as an easy way to display, print, or save only these fields for a set of records and is included for unique record identification purposes.

ORNG

about

an

and

are

been

but

by

do

for

from

has

have

if

in

into

is

it

its

of

on

or

than

that

the

their

these

they

this

those

to

was

were

what

when

where

which

while

will

with

- Gigiena i Sanitariya.  For English translation, see HYSAAV.
 - (V/O Mezhdunarodnaya Kniga, 113095 Moscow, USSR)  V.1-  1936-
 - v. 49(4), p. 87, 1984 (GISAAA)
[note that an issue or supplement number is given].

 - Environmental Mutagenesis.  (New York, NY)  V.1-9, 1979-87.
 - For publisher information, see EMMUEG.  v. 4, p. 667, 1982 (ENMUDM)
[contains reference to publisher information - see directly below].

- National Cancer Institute Carcinogenesis Technical Report
 - Series.  (Bethesda, MD)  No.0-205. For publisher information,
 - see NTPTR*.  NCI-TR-118, 1978 (NCITR*)
[report reference].

 - Environmental and Molecular Mutagenesis.  (Alan R. Liss, Inc.,
 - 41 E. 11th St., New York, NY 10003)  V.10-  1987- 
 - v. 22, p. 34, 1993 (EMMUEG)
[see directly above].

 - Personal Communication from J.F. Sina, Merck Institute for
 - Therapeutic Research, West Point, PA 19486, Oct. 26, 1982
 - 26 OCT 82 (SinJF#)
[personal communication].

A glycoside obtained from the plant Adenium boehmianum (Journal of Pharmacology and Experimental Therapeutics.  (Williams & Wilkins Co., 428 E. Preston St., Baltimore, MD 21202)  V.1-  1909/10-  v. 111, p. 365, 1954 - JPETAB)
[contents of the chemical definition (CD) field for abobioside].

Arab Republic of Egypt
Letter from: National Institute of Occupational Safety and Health, Heliopolis, A.R.E.
Mrs. Laila El Hariry,
General Director of the International Relations Department

Argentina
Letter from Dr. Carlos Anibal Rodrigues,
Ministerio de Trabajo y Seguridad Social de la Nacion
Buenos Aires, Argentina

Australia
Occupational Safety and Health Series, No. 37
Occupational Exposure Limits for Airborne Toxic Substances
International Labour Office, Geneva

Austria
Maximale Arbeitsplatz-Konzentrationen
Gesundheitsschaedlicher Arbeitsstoffe
MAK-Werte-Liste

Belgium
see entry for Australia

Colombia
Letter from: Consejo Colombiano de Seguridad
Renan Alfonso Rojas Gutierrez,
Executive Director

Denmark
Grænseværdier for stoffer og materialer
Copenhagen

France
Valeurs limites d'exposition professionnelle
Aux agents chimiques TABen France

Germany
Deutsche Forschungsgemeinschaft
List of MAK and BAT Values, 1974
Commission for the Investigation of Health Hazards of Chemical Compounds In the Work Area
Report No. 30

Hungary
Letter from: ORSZAGOS
Munkavedelmi Tudomanyos Kutató Intézet
Dr. Jenó Molnar, Director

India
Directorate General Factory Advice Service and Labour Institute
Government of Industry, Ministry of  Labour
H. N. Gupta, Director General

Japan
see entry for Australia

Jordan
Letter from: The Hashemite Kingdom of Jordan
Vocational Training Corporation
Occupational Safety and Health Institute
A. Abdel-Jaber,
Director

Korea
Korea Industrial Safety Corporation (KISCO)
Industrial Safety and Health Research Institute
Seoul, Korea
Park Pil-Soo,
December 21, 1996

The Netherlands
De Nationale MAC-lijst - 1995 - P 145

New Zealand
Letter and booklet (Workplace Exposure Standards) from:
Occupational Safety and Health General Manager's Office
Wellington, New Zealand
Phillip Marshal, Information Manager

Norway
Letter and list from:
Direktortet for Arbeidstilysnet
Oslo, Norway
Nils-Petter Wedege,
Deputy Director-General

The Philippines
Letter from: Republic of the Philippines,
Occupational Safety and Health Center;
Department of Labor and Employment
Evelyn F. Tablang, Officer-in-Charge

Poland
Interdepartmental Commission for Updating the Register of Maximum Allowable Concentrations and Intensities for Harmful Agents in the Working Environment
Ministry of Labour and Social Policy
Poland

Portugal
Letter from Instituto de Desenvolvimento e Inspecçao das Condiçoes de Trabalho Alvaro Durao
O Vice-presidente
Lisboa, Portugal

Russia
Occupational Exposure Limits for Airborne Toxic Substances
International Labour Office, Geneva

Singapore
Letter from: Republic of Singapore
Department of Industrial Health
Ministry of Labour
Tan Kia Tang, Director

Sweden
Statute Book of the Swedish National Board of Occupational Safety and Health:
Occupational Exposure Limit Values

Switzerland
Valeurs limites d'exposition and postes de travail
SUVA-CNA-INSAI

Thailand
Letter and table of values from:
National Institute for the Improvement of Working Conditions and Environment (NICE)
Department of Labour
Bangkok, Thailand
Dr.Chaiyuth Chavalitnitikul, Director

Turkey
Letter from: Occupational Health and Safety Institute P.K. 393
06443 Yenisehir
Ankara, Turkey
Dr. Handan Uysal Sabir, Director

United Kingdom
Occupational Exposure Limits
Guidance Note EH 40/95
Health and Safety Executive

A

M

Spinal Cord

N

Peripheral Nerve and Sensation

P

Sense Organs and Special Senses (Nose, Eye, Ear, and Taste)

Q

Autonomic Nervous System

R

Behavioral

T

Cardiac

V

Y

Gastrointestinal

Z

 Abbreviation - brd
 Species - Bird - domestic or laboratory; Bird not otherwise identified
 Weight - 1 kg

 Abbreviation - bwd
 Species - Bird - wild bird species
 Weight - 40 gm

Abbreviation - cat
 Species - Cat, adult
 Weight - 2 kg
 Consumption Food gm/day - 100
 (Approx.) Water ml/day - 100
 1ppm in Food Equals in mg/kg/D - 0.05
 Approximate Gestation Period in Days - 64 (59-68)

 Abbreviation - chd
 Species - Child
 Age - 1-13 Y
 Weight - 20 kg

 Abbreviation - ckn
 Species - Chicken, adult (male or female)
 Age - 8 W
 Weight - 800 gm
 Consumption Food gm/day - 140
 (Approx.) Water ml/day - 200
 1ppm in Food Equals in mg/kg/D - 0.175

 Abbreviation - ctl
 Species - Cattle, horse
 Weight - 500 kg
 Consumption Food gm/day - 10000
 1ppm in Food Equals in mg/kg/D - 0.02
 Approximate Gestation Period in Days - 284 (279-290)

Abbreviation - dck
 Species - Duck, adult (domestic)
 Age - 8 W
 Weight - 2500 gm
 Consumption Food gm/day - 250
 (Approx.) Water ml/day - 500
 1ppm in Food Equals in mg/kg/D - 0.1

 Abbreviation - dog
 Species - Dog, adult
 Age - 52 W
 Weight - 10 kg
 Consumption Food gm/day - 250
 (Approx.) Water ml/day - 500
 1ppm in Food Equals in mg/kg/D - 0.025
 Approximate Gestation Period in Days - 62 (56-68)

Abbreviation - dom
 Species - Domestic animals - goat, sheep
 Weight - 60 kg
 Consumption Food gm/day - 2400
 1ppm in Food Equals in mg/kg/D - 0.04
 Approximate Gestation Period in Days - G: 152 (148-156); S: 146 (144-147)

 Abbreviation - frg
 Species - Frog, adult
 Weight - 33 gm

 Abbreviation - gpg
 Species - Guinea pig, adult
 Weight - 500 gm
 Consumption Food gm/day - 30
 (Approx.) Water ml/day - 85
 1ppm in Food Equals in mg/kg/D - 0.06
 Approximate Gestation Period in Days - 68

 Abbreviation - grb
 Species - Gerbil
 Weight - 100 gm
 Consumption Food gm/day - 5
 (Approx.) Water ml/day - 5
 1ppm in Food Equals in mg/kg/D - 0.05
 Approximate Gestation Period in Days - 25 (24-26)

Abbreviation - ham
 Species - Hamster
 Age - 14 W
 Weight - 125 gm
 Consumption Food gm/day - 15
 (Approx.) Water ml/day - 10
 1ppm in Food Equals in mg/kg/D - 0.12
 Approximate Gestation Period in Days - 16

 Abbreviation - hmn
 Species - Human
 Age - Adult
 Weight - 70 kg

 Abbreviation - hor
 Species - Horse, donkey
 Weight - 500 kg
 Consumption Food gm/day - 10000
 Approximate Gestation Period in Days - H: 339 (333-345); D: 365

 Abbreviation - inf
 Species - Infant
 Age - 0-1 Y
 Weight - 5 kg

 Abbreviation - mam
 Species - Mammal - species unspecified
 Weight - 200 gm

 Abbreviation - man
 Species - Man
 Age - Adult
 Weight - 70 kg

Abbreviation - mky
 Species - Monkey
 Age - 2.5 Y
 Weight - 5 kg
 Consumption Food gm/day - 250
 (Approx.) Water ml/day - 500
 1ppm in Food Equals in mg/kg/D - 0.05
 Approximate Gestation Period in Days - 165

Abbreviation - mus
 Species - Mouse
 Age - 8 W
 Weight - 25 gm
 Consumption Food gm/day - 3
 (Approx.) Water ml/day - 5
 1ppm in Food Equals in mg/kg/D - 0.12
 Approximate Gestation Period in Days - 21

Abbreviation - nml
 Species - Non-mammalian species

 Abbreviation - pgn
 Species - Pigeon
 Age - 8 W
 Weight - 500 gm

 Abbreviation - pig
 Species - Pig
 Weight - 60 kg
 Consumption Food gm/day - 2400
 1ppm in Food Equals in mg/kg/D - 0.041
 Approximate Gestation Period in Days - 114 (112-115)

 Abbreviation - qal
 Species - Quail (laboratory)
 Weight - 160 gm

Abbreviation - rat
 Species - Rat, adult female
 Age - 14 W
 Weight - 200 gm
 Consumption Food gm/day - 10
 (Approx.) Water ml/day - 20
 1ppm in Food Equals in mg/kg/D - 0.05
 Approximate Gestation Period in Days - 22

 Abbreviation - rat
 Species - Rat, adult male
 Age - 14 W
 Weight - 250 gm
 Consumption Food gm/day - 15
 (Approx.) Water ml/day - 25
 1ppm in Food Equals in mg/kg/D - 0.06

 Abbreviation - rat
 Species - Rat, adult, sex unspecified
 Age - 14 W
 Weight - 200 gm
 Consumption Food gm/day - 15
 (Approx.) Water ml/day - 25

Abbreviation - rat
 Species - Rat, weam; omg
 Age - 3 W
 Weight - 50 gm
 Consumption Food gm/day - 15
 (Approx.) Water ml/day - 25
 1ppm in Food Equals in mg/kg/D - 0.3

 Abbreviation - rbt
 Species - Rabbit, adult
 Age - 12 W
 Weight - 2 kg
 Consumption Food gm/day - 60
 (Approx.) Water ml/day - 330
 1ppm in Food Equals in mg/kg/D - 0.03
 Approximate Gestation Period in Days - 31

 Abbreviation - sql
 Species - Squirrel
 Weight - 500 gm
 Approximate Gestation Period in Days - 44

Abbreviation - tod
 Species - Toad
 Weight - 100 gm

Abbreviation - trk
 Species - Turkey
 Age - 18 W
 Weight - 5 kg

 Abbreviation - wmn
 Species - Woman
 Age - Adult
 Weight - 50 kg
 Approximate Gestation Period in Days - 270

ACGIH

 American Conference of Governmental Industrial Hygienists

H

 hour

asn

 Aspergillis nidulans

ham

 hamster

ast

 Ascites tumor

hla

 HeLa cell

ATSDR

 Agency for Toxic Substances and Disease Registry

hma

 host

bcs

 Bacillus subtilis

hmi

 Haemophilus influenzae

bfa

 body fluid assay

hmn

 human

BHR

 Beilstein Handbook Reference

hor

 horse, donkey

bmr

 bone marrow

I

 intermittent

brd

 bird (domestic)

ial

 intraaural

BRN

 Beilstein Reference Number

IARC

 International Agency for Research on Cancer

bwd

 wild bird species

iat

 intraarterial

C

 continuous

ice

 intracerebral

ca

 carcinogen

icv

 intracervical

cc

 cubic centimeter

idr

 intradermal

CFR

 Code of Federal Regulations

idu

 intraduodenal

chd

 child

ihl

 inhalation

ckn

 chicken

imm

 immersion

CL

 ceiling concentration

imp

 implant

clr

 Chlamydomonas reinhardi

ims

 intramuscular

ctl

 cattle

inf

 infant

cyt

 cytogenetic analysis

ipc

 intraplacental

D

 day

ipl

 intrapleural

dck

 duck

ipr

 intraperitoneal

DEF

 definition

irn

 intrarenal

DHHS

 Department of Health and Human Services

isp

 intraspinal

dlt

 dominant lethal strain

itr

 intratracheal

dmg

 Drosophila melanogaster

itt

 intratesticular

dna

 DNA adduct

iu

 international unit

dnd

 DNA damage

IUPAC

 International Union of Pure and Applied Chemistry

dni

 DNA inhibition

iut

 intrauterine

dnr

 DNA repair

ivg

 intravaginal

dns

 unscheduled DNA synthesis

ivn

 intravenous

dom

 domestic

kdy

 kidney

DOT

 Department of Transportation

kg

 kilogram

dpo

 Drosophila pseudo obscura

klp

 Klebsiella pneumoniae

emb

 embryo

L

 liter

EPA

 Environmental Protection Agency

LC50

 lethal concentration, 50 percent kill

esc

 Escherichia coli

LCLo

 lowest published lethal concentration

eug

 Euglena gracillis

LD50

 lethal dose, 50 percent kill

eye

 administration into the eye (irritant)

LDLo

 lowest published lethal dose

fb

 fiber

leu

 leukocyte

fbr

 fibroblast

liq

 liquid

frg

 frog

lng

 lung

gm

 gram

LOQ

limit of quantitation

gpg

 guinea pig

lvr

 liver

grb

 gerbil

lym

 lymphocyte

grh

 grasshopper

M

 minute

pig

 pig

m3

 cubic meter

ppb

 parts per billion (v/v)

mam

 mammal (species unspecified)

pph

 parts per hundred (v/v) (percent)

mg

 milligram

ppm

 parts per million (v/v)

mky

 monkey

ppt

 parts per trillion (v/v)

mL

 milliliter

pre

 prior to copulation

MLD

 mild irritant effect

preg

 pregnant

mmo

 mutation in microorganism

qal

 quail

mmol

 millimole

rat

 rat

mmr

 mammary gland

rbt

 rabbit

mnt

 micronucleus test

rec

 rectal

MOD

 moderate irritation effect

REGS

 Standards and Regulations

mol

 mole

REL

 Recommended Exposure Level

mppcf

 million particles per cubic foot

rns

 rinsed with water

mrc

 gene conversion and mitotic recombination

RTECS

 Registry of Toxic Effects of Chemical Substances

msc

 mutation in mammalian somatic cells

S

 second

MSHA

 Mine Safety and Health Administration

sal

 salmon

mtr

 morphological transform

sat

 Salmonella typhimurium

mul

 multiple routes

sce

 sister chromatid exchange

mus

 mouse

SCP

 Standards Completion Program

NCI

 National Cancer Institute

scu

 subcutaneous

ng

 nanogram (one billionth of a gram, 1.0E 9 gram)

SEV

 severe irritation effect

NIOSH

 National Institute for Occupational Safety and Health

skn

 administration onto the skin

nml

 non mammalian species

sln

 sex chromosome loss and nondisjunction

nmol

 nanomole

slt

 specific locus test

NOES

 National Occupational Exposure Survey

slw

 silkworm

NOHS

 National Occupational Hazard Survey

smc

 Saccharomyces cerevisiae

nsc

 Neurospora crassa

spm

 sperm morphology

NTIS

 National Technical Information Service (USA)

sql

 squirrel

NTP

 National Toxicology Program

srm

 Serratia marcescens

OBS

 obsolete (trade name)

ssp

 Schizosaccharomyces pombe

ocu

 ocular

STEL

 Short Term Exposure Limit

OEL

 Occupational Exposure Limit

TC

 toxic concentration (other than lowest)

ofs

 other fish

TDLo

 lowest published toxic dose

oin

 other insects

tes

 testis

omi

 other microorganisms

TLV

 Threshold Limit Value

oms

 other mutation test systems

tod

 toad

open

 open irritation test

trk

 turkey

orl

 oral

trn

 heritable translocation test

ORM

 Other Regulated Materials (DOT)

TWA

 time weighted average

OSHA

 Occupational Safety and Health Administration

ug

 microgram

oth

 other cell types

umole

 micromole

ovr

 ovary

unr

 unreported

par

 parenteral

USAF

 United States Air Force

PEL

 Permissible Exposure Limit (OSHA)

W

 week

pg

 picogram (one trillionth of a gram, 1.0E 12 gram)

wmn

 woman

pgn

 pigeon

Y

 year

pic

 phage inhibition capacity