The COMAH Dataset lists the establishments regulated under the Control of Major Accident Hazards Regulations 2015 in Great Britain (COMAH) and is published monthly by the Health & Safety Executive (HSE).

COMAH regulations apply to the management teams at establishments that handle, store, or produce large quantities of hazardous materials, such as chemicals, explosives, and fuels. Managers are required to inform a Competent Authority (CA) comprising HSE, acting jointly with the appropriate environmental agency (Environment Agency, Natural Resources Wales or Scottish Environment Protection Agency), where quantities of dangerous substances identified in the Regulations are kept or used. Establishments are listed as 'Lower Tier' and 'Upper Tier' based on stored inventory and associated risk status. The higher the quantity of dangerous substances, the more comprehensive the safety measures, planning, and regulatory oversight required.

The COMAH Dataset provides the site operator name and address, the 'tier', Local Authority name (with code) and map coordinates for the postcode unit (i.e. B24 8DN). It is useful for risk analysts, underwriters and actuaries to understand proximity to Major Accident Hazard locations to make optimal pricing and portfolio decisions.