The Control of Substances Hazardous to Health (COSHH) Regulations govern the use of hazardous substances in the workplace in the UK and specifically require an assessment of the use of a substance. Regulation 12 requires that an employer provides employees with information, instruction and training for people exposed to hazardous substances. This duty would be very nearly impossible without the data sheet as a starting point. It is important for employers therefore to insist on receiving a data sheet from a supplier of a substance.