The Fire at Allied Colloids Limited, Low Moor, Bradford. 21st July 1992

Accident summary

The seat of the fire was located in a raw materials warehouse at Allied Colloids site in Low Moor, Bradford. The warehouse itself had two rooms allocated for the storage of oxidising and flammable products known as No.1 and No. 2 oxystores. No. 2 oxystore had steam heating as it was originally designed to store frost sensitive products.

On the morning of the incident steam heated blowers in the warehouse had been turned on to dry out moisture. It is thought that a steam condensate line was responsible for heating a number of AZDN kegs, which were stored at height in the No. 2 oxystore. The heating effect caused two or three of the AZDN kegs to rupture and spill white powder all over the floor. A passing employee thought that the powder was smoke and raised the alarm. It was determined that no immediate hazard was present and the AZDN data sheet was referred to before a clean up plan was devised. While waiting for confirmation from the appropriate vacuum cleaner manufacturer an employee noticed a plume of smoke/vapour and a hissing noise coming from a bag of SPS that was located underneath the AZDN kegs. Before the employee could douse the SPS with water the vapour plume ignited and became a jet flame of about 300 mm in length. Within a few seconds the jet flame became a flash fire which was transmitted all around the room.

It was determined later that the AZDN powder probably mixed with unintended spills of SPS and other oxidising products. AZDN in contact with SPS is likely to have been ignited by an impact, possibly from a lid and associated metal ring closure from one of the damaged AZDN kegs falling onto a bag or the floor.

The fire spread throughout the warehouse and smoke was blown towards nearby motorways. The fire was contained that day and the fire brigade was not stood down until 18 days later due to risk of re-ignition during clean up. Considerable environmental damage to the Aire and Calder rivers resulted from the firewater run off.

Failings in technical measures

• AZDN kegs were stored in the same section of the warehouse as SPS and other oxidising substances, after being wrongly classified in the documentation.
• Segregation of Hazardous Materials: Warehouse storage, Incompatible substances
• Raw Materials Control / Sampling: Safety management systems
• Failure of the steam heating system or operator error meant that heating was applied in No. 2 oxystore as well as in the main warehouse.
• Plant Modification / Change Procedures: Decommissioning procedures
• The oxystores and warehouse were not fitted with adequate smoke detection and fire fighting facilities.
• Active / Passive Fire Protection
• The fire brigade and police should have been informed immediately the first incident had been discovered. As it was there was a 50 minute delay before the fire occurred and the emergency services informed.
• Emergency Response / Spill Control: Site emergency plan, Stabilising to safe condition, fire fighting
• Significant environmental damage was caused to the Aire and Calder rivers by the fire-water run-off.
• Emergency Response / Spill Control: Fire fighting
• Secondary Containment: bunds, catchpots, barriers

References

Health and Safety Executive, 'The fire at Allied Colloids Limited. A report of the HSE's investigation into the fire at Allied Colloids Ltd, Low Moor, Bradford on 21 July 1992', ISBN 0 71 760 707 0, 1993.