Last reviewed 14 October 2021

Briar Chemicals Ltd has been fined £1m after a man died in an explosion at its site in Norwich.

Chelmsford Magistrates’ Court heard how on 27 July 2018, a maintenance contractor, Rob Cranston, was carrying out repair work on a mixing vessel during a planned period of shutdown maintenance. It is thought that his welding torch or grinder accidentally ignited flammable toluene vapour inside the vessel, which should not have been present when the work commenced.

Flammable liquids and vapours such as toluene are found in many places of work. If a welding or plasma torch or powered cutter is used on a tank or drum containing even residual quantities of flammable material (solid, liquid or vapour), the tank or drum can explode violently.

According to HSG140, a major cause of incidents is hot work (welding, cutting or similar operations) carried out on vessels containing flammable vapour or liquid residues. Thus, hot work should only be carried out under controlled conditions using a permit-to-work system. This will include following site rules and instructions and operating only when authorised by a responsible person. Hot work must not be carried out on an item that contains or has contained flammable liquid or vapour until the item is made safe.

Investigating Health and Safety Executive officers found that a quantity of toluene residue had been left inside the vessel after shutdown cleaning at the beginning of June 2018. Two damaged valves situated above the vessel in the toluene supply pipe were also found to be leaking. Workers had been instructed to transfer a large quantity of toluene from one storage tank to another through this pipe which allowed additional flammable liquid to leak into the vessel which was supposed to be empty and clean.

Briar Chemicals Ltd pleaded guilty to a breach of regulation 5 of the Control of Major Accident Hazards Regulations 2015. The company was fined £1 million and ordered to pay costs of £10,967.20.

Companies handling or storing flammables are reminded to consider the potential risk of fire and explosion and ensure they have robust procedures in place to minimise and control risk at all times, including during planned maintenance work.