Oxford University: Chemical Safety and Other Information - an excellent site with many good links
The Oxford contains the following information:
Carcinogens || CAS numbers || Common chemicals || Flash points (low) || Foreign-language databases || Gases || Glossary
Glove materials || Hazard Codes || Highly toxic compounds || Incompatibles || Maximum Exposure Limits || MSDS Data Sheets Peroxides || Risk and Safety Phrases || Shock-sensitive Materials || Chemical Synonyms || Templates || Teratogens
This is another excellent homepage with many, many links to other data bases and tutorials.