The Explosion and Fire at Chemstar Limited. 6th September 1981

Accident summary

Chemstar Limited was a small chemical company specialising in solvent recovery. The site was based in Stalybridge on the outskirts of Manchester. The explosion and subsequent fires occurred at approximately 23.30 hours on the night of 6 September 1981 resulting in one fatality.

At the time of the accident the main water supply to the Chemstar site had been cut, due to draining of the local reservoir, and the plant was running on a temporary water supply which was pumped from a nearby stream. For several days prior to the explosion, difficulties had been experienced with the temporary water supply, both with the diesel pump and another undiagnosed problem.

The cause of the explosion was due to an interruption in the water supply to the condenser of a hexane still. The still contained 6000 litres of hexane, which was being distilled to remove contaminants.

An employee initially noticed a strong vapour smell coming from the distillation room and after reducing the supply of steam to the still noticed that the water supply to the condenser had ceased. The employee and a delivery truck driver (on site to load his truck) started to investigate the loss of water. It is thought that the oil-fired boiler, which was supplying the steam, ignited the hexane vapours and caused the subsequent explosion.

The explosion killed the truck driver who was in the building at the time and the employee suffered severe burns. The fire spread to the rest of the site and at the height of the fire 37 fire appliances were in attendance.

Failings in technical measures

• The temporary water supply that was being used had suffered several interruptions over previous days and failed before the accident, causing the release of hexane vapours.
• Reliability of Utilities: required availability
• The discharge vent from the condenser was located inside the building allowing vapours to collect in the distillation room and reach the boiler.
• Relief Systems / Vent Systems
• The operator was trained to use continuous distillation equipment and was unfamiliar with the batch processing system and the valve settings for normal and emergency operation.
• Training: operator training, emergency planning training

References

Health and Safety Executive, 'The explosion and fire at Chemstar Limited, 6 September 1981', ISBN 0 11 883 666 8, 1982.