Search SciFinder for a substance. If CHEMLIST data is available for that substance, there will be a link from the substance record. CHEMLIST includes various state, federal, and foreign regulatory information but is not comprehensive.
A subset of PubChem compounds contain safety information in the form of Laboratory Chemical Safety Sheets (LCSS) linked from the tops of their records. For other chemicals, navigate to the Safety and Hazards section of the record for relevant information.
These are some aggregators of SDS information. Remember that, in industry, you must use the SDS associated with the manufacturer/vendor of the chemical. A simple Google search can help you find SDS information for specific chemicals from particular vendors, and most vendors and manufacturers also post this information publicly in their product catalogs.