The link:  http://www.epa.gov/iris/index.html 

Tool 
Integrated Risk Information System (IRIS) is prepared and maintained by the U.S. Environmental Protection Agency (U.S. EPA) 

Purpose 
IRIS is an electronic database containing information on human health effects that may result from exposure to various chemicals in the environment. The information in IRIS is intended for those without extensive training in toxicology, but with some knowledge of health sciences.

Description 
List all chemicals and select one of the names and all available information about this material are shown. The user can search on; Substance Name or CASRN, Keyword, Health effect, Evidence for Human Carcinogenicity or Quantitative Toxicity and Related Values.