An abbreviation for Control of Major Accidents and Hazards. These UK regulations under the Health and Safety at Work Act require the operator of a process plant or site that contains more than a defined amount of hazardous chemicals to provide a safety case report for the process and its operations, to demonstrate that it can be operated in a (p. 73) safe and environmentally acceptable manner. The regulations have control of manufacturing sites with major pollution potential and superseded the earlier CIMAH regulations in 1999.