A material safety data sheet (MSDS) is to be provided by the seller for every cleaning product purchased and by the service provider for every cleaning chemical used by an outside firm on your property. These sheets contain a significant amount of important information covering such items as the product’s manufacturer, any hazards, recommended first aid measures, handling and storage procedures, toxicology and disposal protocol. Each MSDS sheet is required to be updated every three years or whenever a potentially hazardous ingredient is added or removed, so it is a good idea to sift through your files to see if any MSDS sheets need to be updated.