Features of the RTECS Database

RTECS is a definitive toxicological database with supplemental information pertinent to both the chemical industry and the occupational safety and health community. This technical data is needed to assess workers’ exposures to chemicals, particularly to lesser-known-and-used chemical substances. OSHA has designated RTECS as a primary source for toxicity data for Material Safety Data Sheets in its Hazard Communications Rule. In recent years RTECS has grown to include more than 160,000 chemicals. The toxicological data are organized into six fields: primary irritation, mutagenic effects, reproductive effects, tumorigenic effects, acute toxicity and multiple dose toxicity. Each data line includes the citation to its bibliographic source. RTECS provides a host of reference data including, but not limited to: CAS Numbers, OSHA PELS, ACGIH TLVs, NIOSH RELS, Carcinogenic assessments, Beilstein Reference Numbers, and Bioassay results from the National Toxicology Program.

An individual RTECS record may include as little as a single toxicity citation in addition to identifiers, or it may contain multiple citations, in the cases of widely studied substances. Benz(a)pyrene, for example, contains more than 300 toxicity lines.

The synonym field has been valuable to the users of the RTECS database. Many chemicals have been known by various names. The names originate from use of different chemical nomenclature systems, common names, foreign names, and often trade names. A user often knows only a single name. Since RTECS maintains an extensive synonym field, users can access the appropriate records when searching RTECS.

The following is a brief description of the six toxicity fields.

First, the primary irritation data are derived from the Draize test results. The Draize test provides information on skin and eye irritation. The studies are conducted on selected mammalian species, primarily the rabbit.

Second, the mutagenic effect data field provides only positive test result data. It includes 20 specific test systems, both in vitro and in vivo. The end point of this field describes an exposure concentration rather than an administered dose, and may be expressed on a weight/volume basis of weight per plate, well, or disc. Tested organisms may include bacteria, molds, yeast, protozoa, insects, and various cell types.

Third, the reproductive effect data include not only teratogenic data, but effects on male and female parents, effects on fertility, developmental abnormalities, effects on the embryo or fetus, tumorigenic effects, and effects on the newborn. Each data line identifies the time and duration of the study, as well as the gestation period of the test. The doses that are noted are cumulative for the total test period.

Fourth, the tumorigenic effect data has three major types: “carcinogenic by RTECS criteria,” “neoplastic by RTECS criteria,” and “equivocal tumorigenic results.” As with the reproductive data, tumorigenic data end points are cumulative figures, representing the total dose administered over the designated test period.

Fifth, the acute toxicity data field is the largest of the toxicity fields, and contains mostly single dose lethality data. The most common measure of acute toxicity is the LD50 (or the LC50 for inhalation). This is a statistical figure denoting the dose level at which 50% of the test population is expected to expire. When insufficient data are available for a determination of LD50 or LC50, the lowest concentration in the test protocol in which lethality occurred is cited and labeled LDLo or LCLo.

Sixth, the multiple dose toxicity data is actually a collection of chronic data with toxic, but not lethal effects noted. The end points are expressed as TD or TC with route-species, dosage level, and duration of study. A sample line might read: R12Y30Z01 oral rat TD: 100 mg/kg, 26 W(weeks). The actual effects noted are described by the toxic effects codes preceding the numerical end point. These codes describe the effects that occur at the dosage level indicated. The toxic effect codes are an integral part of this field. These codes are structured in a three position alphanumeric format. The first position (alphabetic) indicates the organ, tissue or functional system described, and the second and third position (numeric) denote specific damage produced. Listed .

below are the alphabetic codings:

A. Brain and covering

B. Spinal Cord

C. Peripheral nerve and sensation

D. Sense organs and special senses (nose, eye, ear, and taste)

E. Autonomic nervous system

F. Behavioral

G. Cardiac

H. Vascular

J. Lung, thorax, or respiration

K. Gastrointestinal

L. Liver

M. Kidney, ureter, and bladder

N. Endocrine

P. Blood

Q. Musculosketal

R. Skin and appendages

S. Immunological Including Allergic

T. Reproductive

U. Nutritional and gross metabolic

V. Tumorigenic

Y. Biochemical

Z. Related to chronic data

The Review Field of RTECS is composed of three sections: Threshold Limit Values(TLVs) from the ACGIH, carcinogenic assessments from the International Agency for Research on Cancer (IARC), and citations to articles of general toxicological interest containing the subject chemical. The IARC monographs are accepted as definitive assessments of carcinogenic risk to animals and humans from exposures to chemicals.

The standards and regulations field includes regulations pertaining to chemical exposures, notably the OSHA PELS, the MSHA Air Quality Standards, and the EPA FIFRA standards. Moreover, there is a listing of the International Occupational Exposure Levels from a number of nations around the world.

The final field in the file is status, and it lists the status of various governmental programs pertaining to the specific substance accessed. The EPA program status under the Toxic Substance Control Act (TSCA), entries in the TSCATS database, GENETOX, and Iris are all noted in this field. The National Toxicology Program bioassay test status and citations from the current issue of the Annual Report on Carcinogens are also noted in the status field.

As can be seen from this overview of the contents of RTECS, a huge quantity of information is at the command of the user. The added advantage is by carefully designed search strategies; highly specific subfiles can be extracted and downloaded. RTECS has been designed to offer optimum assistance to those who need information about chemical hazards. For any organization needing to produce MSDS’s, the OSHA Hazards Communication Rule has designated RTECS as a prime source of toxicity data.