CDC ASTDR Data Bases Mega Site CDC’s ASTSDR Massive site, massive info on environmental health, chemicals, current legislation, more w/links to other key US data bases http://www.atsdr.cdc.gov/
NIH's National Toxicology Program Research facilities help determine risk scenarios for various chemicals used by USEPA & many others in legislation, enforcement action, warnings. http://ntp.niehs.nih.gov/