The Flixborough disaster was an explosion at a chemical plant in the village of Flixborough near to Scunthorpe, North Lincolnshire, England. The disaster happened on 1 June 1974. It killed 28 people and seriously injured 36.
The chemical plant was in operation since 1967. The plant produced caprolactam, a feed stock for the manufacture of nylon.
The process involved oxidation of cyclohexane with air in a series of six reactors to produce a mixture of cyclohexane and cyclohexanone. Some 8 weeks before the explosion a crack was observed in the number 5 reactor. It was decided to install a temporary 50 cm (20 inch) diameter pipeline to bypass the leaking reactor to allow continued operation of the plant while a new reactor was manufactured.  
Although not directly related to urea processes, this case is an example of the same risks atmospheric corrosion can introduce in a urea plant.