Making industry safer: The lessons of the Nypro chemical disaster

41 years ago this month, one of Britain’s biggest peacetime explosions ripped through the Nypro chemical plant at Flixborough near Scunthorpe. 28 workers died, the plant was destroyed, extensive damage was done to surrounding homes, but its legacy enhanced industrial safety. Fire and Safety Centre recalls one of Britain’s biggest peacetime explosions and the history behind it.

More than four decades after what was, at the time, the largest-ever peacetime explosion in Britain, chemical engineering students are still taught the lessons learned from a summer Saturday afternoon catastrophe.

The event was the Nypro explosion, which happened at Flixborough on the banks of the River Trent in North Lincolnshire just before 5pm on Saturday 1st June 1974. It claimed the lives of 28 people, and many more suffered personal injuries.

The death toll could have been much higher, but because the explosion took place on a Saturday, the offices were unoccupied when they were flattened by an exploding cloud of cyclohexane gas.

What caused the Nypro explosion?

Nypro ExplosionThe Nypro explosion happened because a temporary pipe, on a chemical plant making material to produce nylon, had been fitted to by-pass the space occupied by a large reactor vessel that had been removed for repair. When a flexible bellows next to the temporary pipe failed, it allowed the cyclohexane, boiling and in many respects similar to petrol, to escape. This ignited causing the explosion.

At the time the UK not only had no specific regulations to control major industrial hazards, but didn’t understand them fully anyway. Robin Turney, a Fellow of the organisation IChemE, said:

“Flixborough has left a lasting legacy on the chemical and process industries – in the UK, Europe and worldwide. “The accident occurred in an era where early but concerted efforts were being made to improve safety. Flixborough coincided with the introduction of Health and Safety at Work Act in the UK, and spurred the development of the European Seveso Directive – named after an accident at a chemical manufacturing plant in Italy in 1976 – strengthening regulation further in 1982.”

The cost of the Nypro Explosion

By March 1975 the financial cost had risen to £24m and involved about 6,000 public liability insurance claims, but by the end of that month 96% of house repairs and rebuilding had been completed. That was a significant exercise; out of 912 properties in just three surrounding villages, a mere 123 escaped damage. A further 780 were damaged in Scunthorpe, almost four miles away.

After the disaster, the public face of Nypro, was its personnel Manager Bob Matthews. He was a Rotarian and writing in an anniversary publication for the Scunthorpe Rotary Club, he described how the rebuilding work had been financed:

Rotarian Jack Jill was President of the local builders’ organisation, and raised the problems of cash flow with which they had to contend during the hectic summer of 1974, and the dilatory approach of the insurance companies, especially during a period of high inflation.

As a result, Nypro provided interest-free loans to builders, and persuaded Royal Insurance to meet Nypro’s £1m public liability insurance claim immediately at a meeting with the British Insurance Association.

The explosion gave the world safety lessons it still heeds today, not only in chemical plants but also in other processing industries including oil, gas, and pharmaceuticals.

Nypro’s response to the situation won over the residents of Flixborough village, its nearest neighbours. In June 1974 the local evening paper carried the banner headline: ‘Flixborough says ‘never again’, Nypro’. By June 1975 that had changed to: ‘Flixborough gives massive yes to Nypro rebuild’.

• The extent of the dangers posed by the disaster can be seen on the front page of a now defunct weekly newspaper. The picture was taken not on Saturday 1st June, but at least two days later…