HSE points to chemical segregation as key consideration

By the time the fire service arrived, flames were shooting through holes in the roof. An explosion then occurred which broke the glass in the site gatehouse.

15 minutes into the incident another explosion occurred in a store holding oxidising materials. This blew out a roller shutter door, which hit the wall of a building about 10m away. This was now a serious fire engulfing both the oxidising materials store and an acid pen area. Drums of solvents were beginning to explode in the intense heat. Some of these exploding drums were propelled several hundred feet into the air.

The fire also spread to the roof of a nearby building on the boundary of the site and after 30 minutes from the alarm being raised another offsite building 30m away was beginning to be endangered. Several explosions then occurred engulfing the front of this second building. A flying, burning solvent drum also crashed through the roof in the main store area, immediately starting another fire.

Approximately 3,000 residents were evacuated from their homes.

The HSE identified two key failings in technical measures:

• Lack of chemical segregation in the storage of a vast range of chemicals led to the extremely rapid and violent spread of the fire.
• The building was constructed in 1982 in accordance with the building regulations in force at the time. However, later HSE guidance suggests that a more substantial thermal barrier, such as a double brick wall, should have separated the store from the adjacent area containing drums of flammable liquids.