Chemical information from authoritative sources (FREE)

 These are not SDS. Search for a chemical under Compound or Substance, it will return a wealth of information on the material. Results include pharmacological action/classification, safety/toxicology, literature links, physical data, etc. Bioassay and structure searches also available. The Laboratory Chemical Safety Summary (LCSS) system is  useful for laboratory safety. 

These are not SDS. A free chemical structure database providing fast access to millions of structures, properties, and associated information. Nice advanced search options, including structural 

 These are not SDS. Information available in 23 languages. Data includes appropriate regulatory listings under CLP, REACH, and ESR as well as an info card with basic properties and label/hazard information. 

Focused on healthcare agencies such as hospitals and doctor's offices. A mixture of SDS and MSDS PDF files with additional information. Search by product and/or manufacturer. Site has a SDS request form for items not currently in the database.

 The Substance Registry Services (SRS) is EPA's authoritative resource for information about chemicals, biological organisms, and other substances tracked or regulated by EPA. 

State of New Jersey Right to Know Hazardous Substance Fact Sheets searchable by DOT No, CAS No, Chemical Name, or RTK Substance.