Control of Substances Hazardous to Health Regulations apply to virtually all UK workplaces. There are mandatory requirements for employers to carry out coshh risk assessments. Substances hazardous to health are those products that are capable of causing adverse effects or disease arising out of exposure from work activates. It is the employers responsibility to gather information on these products and either eradicate the risk or at least control it. Hazardous substances are those chemicals classified by CHIP and the new CLP regulation.