The operators of COMAH establishments are required to quantify the risk of major accident scenarios and identify the location of the specified area which is defined by the COMAH Regulations as the area that is liable to be affected by an establishment. It may extend outside of the boundary of the establishment. The specified area is determined using a risk based approach in accordance with the Policy & Approach of the Health & Safety Authority to COMAH Risk-based Land-use Planning (19 March 2010).

AWN have experience of modelling the consequences of major accident scenarios, and of quantifying the individual risk of fatality using fault tree analysis, event tree analysis and probit relationships for thermal, overpressure and toxic consequences. QRA is used to assess the impacts of major accident hazards on-site at occupied locations and at off-site locations that are occupied by members of the public. AWN have completed QRA of establishments with major accident hazard potential both as part of compliance with the provisions of the COMAH regulations and for assessing the suitability of development proposals in the vicinity of such establishments.