The report sets out the accidents which were reportable to the European Commission because they met thresholds of damage set out in the EU Seveso Directive on major accident hazards.
In all, the four accidents killed four employees and injured 24 people, but caused no damage to the environment.
Official investigations of only one accident have been completed. They led to a prosecution of Newport waste treatment business Park Environmental for a release of hydrogen sulphide during a waste mixing operation which killed one employee and injured three others. The firm was fined £250,000 in January (ENDS Report 337, p 51 ).
Two accidents occurred within six months of each other at Conoco facilities on Humberside. In the more serious incident, 179 tonnes of flammable hydrocarbons escaped following a failure of overhead pipework at the Killingholme refinery. The gases formed a vapour cloud and exploded, triggering further pipe ruptures and fireballs and causing "extensive" off-site damage to homes and businesses.
The fourth accident was the failure of a blast furnace at the Port Talbot works of steelmaker Corus in November 2001, releasing large quantities of toxic and flammable gas and molten product. Three employees were killed and 17 injured (ENDS Report 322, p 8 ).
"Major accidents" in the two previous years totalled ten and four, and four per year is around the long-term average, according to the HSE. It is working with the chemical industry to cut the figure by 20% by 2004.