Sources of Information 



• Group D - Not Classifiable as to Human Carcinogenicity: 



This group is generally used for agents with inadequate human 

 and animal evidence of carcinogenicity or for which no data 

 are available. 



• Group E - Evidence of Noncarcinogenicity for Humans: This 

 group is used for agents that show no evidence for carcinogeni- 

 city in at least two adequate animal tests in different species or 

 in both adequate epidemiologic and animal studies. The clas- 

 sification of an agent in Group E is based on the available 

 evidence and should not be interpreted as a definitive con- 

 clusion that the agent is not a carcinogen under any circum- 

 stances. 



The above descriptions for the categories were taken from U.S. EPA 

 (1986a). At present, a weight-of-evidence classification for car- 

 cinogenicity is available in IRIS for each chemical assigned a Car- 

 cinogenic Potency Factor. 



In many cases, EPA regions and others may rely on toxicity profiles 

 generated previously. IRIS is a key source of chemical toxicity data, 

 including information from critical studies and weight-of-evidence 

 classifications for carcinogens. The first step in a hazard assessment 

 should be to consult IRIS chemical files for potential contaminants of 

 concern. IRIS chemical files are available for approximately 260 

 chemicals (as of August 1988). Further information on IRIS is 

 provided in Appendix B. 



The primary sources of toxicity profiles are the EPA Office of Waste 

 Programs Enforcement and Office of Health and Environmental As- 

 sessment (e.g., Appendix C, Table C-1). EPA toxicity profiles are 

 available for approximately 195 chemicals. Additional sources are 

 shown in Appendix C, Table C-2. Under the Superfund Amendments 

 and Reauthorization Act of 1986, EPA and the Agency for Toxic 

 Substances and Disease Registry are preparing toxicity profiles for 100 

 hazardous substances considered as high priority contaminants at 

 Superfund sites. 



Supplementary information on the toxicity of contaminants of concern 

 may be obtained from bibliographic or chemical/toxicological 

 databases. DIALOG, a comprehensive bibliographic database system 

 (Dialog Information Services, Inc., 3460 Hillview Avenue, Palo Alto, 

 CA 94304), offers access to databases such as Pollution Abstracts, 

 National Technical Information Service, and ENVIROLINE. Chemi- 

 cal and toxicological information can be obtained from the databases 

 listed in Appendix C, Table C-3. In particular, MEDLARS and its 

 associated databases (e.g., Toxline, RTECS, and AQUIRE) provide 

 extensive toxicological information. 



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