Flixborough, 1 June 1974

1 June is the 40th anniversary of the Flixborough disaster, an explosion at a chemical plant sited on the banks of the River Trent in Lincolnshire. It was the biggest explosion to ever occur in Britain (during peacetime), until the fire at the Hertfordshire oil storage terminal (Buncefield) in December 2005. At Flixborough, 28 workers were killed and 36 others onsite suffered injuries. Outside the works, injuries and damage occurred on a widespread scale but there were no fatalities.  It was recognised that the number of casualties would have been even higher had the incident occurred on a weekday.

The explosion was estimated to be equivalent to 16 tonnes of TNT and the subsequent fires raged for ten days. A considerable amount of property was destroyed in Flixborough and the surrounding villages, and the explosion was heard over 30 miles away in Grimsby. The Atomic Weapons and Research Establishment at Aldermaston produced a report on the infrasonic and seismic waves which resulted. 

The Flixborough Plant before the explosion - official report, TS 84/37/1

The Flixborough Plant before the explosion - official report, TS 84/37/1

Massive explosion

The plant, owned by Nypro UK, produced caprolactum, a chemical used in the manufacture of nylon.  Some two months before the disaster, a crack was found in one of the reactors. A pipe was installed to bypass the leaking reactor so that the plant could continue production. During the late afternoon on 1 June 1974 the temporary bypass pipe ruptured, and a huge quantity of cyclohexane leaked from the pipe, forming a vapour cloud which then found a source of ignition. The massive explosion destroyed the plant. Eighteen fatalities occurred in the Control Room as a result of the windows shattering and the roof collapsing.

The Flixborough Plant after the explosion is a scene of devastation

The Flixborough Plant after the explosion - Official Report, TS 84/37/1

 Official Report

The official report into the accident (published in 1975) found that the bypass pipe had failed because of unanticipated stresses in the pipe during a pressure surge –  the pipe had been inadequately supported, and the modification had been made without a full assessment of all the potential factors. Following the disaster there was a huge public debate about the safety of industrial plants and regulations regarding industrial processes were made considerably more rigorous – the newly formed Heath and Safety Commission took a close interest in these developments.

Reactors 4 and 6 soon after the explosion

Reactors 4 and 6 soon after the explosion - Official Report, TS 84/37/1

 New theories

New theories about the causes of the disaster have been advanced since 1975, notably by engineer Ralph King and Dr John Cox. Ralph King suggested that a reaction between water (which had settled in one of the reactors) and the hot cyclohexane above it caused a massive rise in pressure that blew apart the piping. The causes of the disaster were complex (it is impossible to do justice to all the technical explanations here) and the debate continues.

The fires as seen from the south-west - a massive conflagration

The fires as seen from the south-west - Official report, TS 84/37/1


The National Archives holds a great deal of documentation about the disaster and its aftermath, including numerous plans, drawings, photographs and witness statements as well as the Report of the Court of Inquiry. Witness statements include vivid accounts by onsite workers  – powerful testimony describing the sudden descent into hellish conditions, and nightmarish experiences, such as this extract from a statement: ‘I felt the blast from a terrific explosion which had occurred somewhere behind me. The blast was such that it threw me full length across the road. Debris then began to fall all around me and I was covered with oil which fell out of the sky’ (LAB 104/387).

Evidence such as this conveys the horrific nature of that cataclysmic explosion 40 years ago – a terrible tragedy that had a major impact on health and safety practices in the UK.


  1. […] Flixborough, 1 June 1974 May 31, 2014 Filed In Journals & Publications 1 June is the 40th anniversary of the Flixborough disaster, an explosion at a chemical plant sited on the banks of the River Trent in Lincolnshire. It was the biggest… Go to Source « […]

  2. David Gardiner says:

    I was stationed in RAF Scampton when the disaster occurred, and I certainly heard the explosion. Soon after, during an evening dance at RAF Scampton, the duty SNCO stopped the dance and called for volunteers to help with the disaster. Many of those Royal Air Force personal at the dance went to help and the local nurses that were there returned to their posts at Lincoln Hospital to help deal with the emergency.

  3. Rachel Sargeant says:

    My grandfather in Grimsby heard the explosion and thought it was very strange thunder. My other grandfather in Scunthorpe said it blew the front door open. I was a young child at the time and remember the veil of tragedy that fell over that part of Lincolnshire. One of the teachers at my school lost a relative in the explosion.

  4. Mike Bensley says:

    I remember that day very well,I was breaking a young pony at Barrow Haven near the bank of the Humber, a very loud explosion followed by a plume of smoke. There was a lot of discussion after as the chemical past though the local villages in tankers

  5. Michael Jones says:

    I was News Editor of The Sunday Times when the explosion happened. We were between editions and cleared as much space as we could to cover it. We hired an aircraft from Biggin Hill for aerial photos and hit the phones. Fortunately, I had a technical report about Flixborough in a personal file I kept in the event of such crises. It contained graphic information about the plant which gave us an invaluable insight into its construction. It was so informative, we had an argument about whether to focus on the disaster itself or the possible causes of it. I won that skirmish with a more senior editor, a rare event, and look back on that tragic night satisfied that we did everything we could to beat the clock and the opposition.

  6. Peter Dodd says:

    Flixborough brings back memories of when I was Chartering Manager at British Steel Corporation and, until the new iron ore berth was completed at Immingham, in the early 70s we were forced to tranship iron ore at Rotterdam and bring it to Flixborough to feed the steel works at Scunthorpe.

    We had a contract with a Hamburg firm and, if my aged memory serves me correctly, we were bringing in 30,000 tonnes a week in small coasters. We used to have one ship alongside and one or two waiting in the Humber to come up the Trent on the tide. Flixborough did us proud – a remarkable little port.

  7. […] National Archives: The Flixborough Disaster includes links to the official report on the tragedy, which you can also find […]

  8. Bob Myers says:

    I was a serving police constable in Humberside Police and at the time of the incident
    I was shopping in Baxtergate Doncaster with my family when we heard the explosion.
    On returning home to Goole I was called in for duty and with other officers carried out
    anti looting patrols through the night.

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