Canadian Links:
Alberta Environment
Alberta Gazette and Legislation
Canada Gazette
DSL - Domestic Substance List 
Guidance to NSNR
Environment Canada
Health Canada
NPRI - National Pollutant Release Inventory 
Ontario E-Laws
Ontario Environmental Bill of Rights
Ontario Ministry of Environment
Ontario Ministry of Labour
TDG - Transport Canada - Transport Dangerous Goods  
WHMIS - Workplace Hazardous Materials Information System
 

U.S. Links:
California's Proposition 65 (Prop 65 News)
Federal Register Online
NIOSH - National Institute for Occupational Safety and Health
Office of Hazardous Materials Safety
U.S. Department of Labor - Occupational Safety & Health Administration (OSHA) 
U.S. Environmental Protection Agency 
U.S. Food and Drug Administration

European Links:
IARC - International Agency for Research on Cancer
ECB Existing Chemicals (EINECS)