Engineer and leading authority on nuclear and chemical safety
The chemical engineer Sir Frederick Warner, who has died aged 100, was internationally renowned for his pioneering work in building chemical plants and improving the health and safety conditions for workers in the chemical industry. His expertise in environmental impact, particularly of radiation, saw him lead the first international team into Chernobyl to assess the damage caused by the catastrophic reactor meltdown in 1986.
Disturbed by the fact that 31 young Soviet soldiers and firefighters had died after exposure to high doses of radiation during the containment operation, he later assembled a group of 100 retired engineers and scientists – Volunteers for Ionising Radiation – who would be available to help during any future such emergencies. After receiving advice from radiobiologists, he reasoned that people who were over 65 would tolerate exposure better than those who were younger and would have fewer concerns over possible genetic effects.
Warner - Ned to his friends - was born in St Pancras, north London, the son of Frederick, a policeman, and his wife, Annie. He was educated at Wanstead national school and Bancrofts school and graduated in chemistry from University College London in 1931. With no hope of finding a job in the middle of the Depression, he returned to UCL for a postgraduate diploma in chemical engineering. A committed communist, anti-war campaigner and passionate rugby player who became president of the University of London Union in 1933, he was so busy with his numerous interests that he had to take his diploma twice before he passed.
He worked as a chemical engineer for various companies before founding the consulting engineers partnership Cremer and Warner in 1956 with his friend Herbert Cremer. The firm worked around the world, in the Soviet Union, India, Iran, Jordan and Africa, solving problems with large-scale chemical plants, air and water pollution and coal and oil gasification. Warner found the Soviets particularly advanced in gasifying coal underground and adapted their ideas for use in North Sea oil exploration. He was particularly pleased with the work the company undertook on the mathematical modelling of flows on the river Thames and its findings on dissolved oxygen levels and sewage station outfalls. This research subsequently led to a significant clean-up of the river, which in turn enabled fish stocks to recover and saw migratory salmon and sea-trout return – having been absent since Victorian times. He retired from the company in 1980.
His international work included the introduction of Camping Gaz to the UK in the 1950s – it was being made in France but could not be sold in Britain because of complex government departmental regulations. Because he spoke French, Warner was asked to translate the company's documentation and advise it on meeting the regulations. This was straightforward for the large cylinders, but the manufacturing process description for the small ones stumped him with a phrase about a "souage" – a word even the French embassy could not help him translate. "One night I woke up and thought – could it mean swage?" he explained. An English dictionary held the answer – the name of that tool comes from the Norman French, souage. "The cylinders were welded on the swage – a bit of lateral thinking can help."
Warner's first job in a chemical works in Stratford, east London, in 1934, fuelled his lifelong interest in health, safety and risk assessment. The factory started making fire suppressants as part of the rearmament effort, which involved the use of methyl bromide, which boils at 4C (39F). With only primitive refrigeration equipment available, the workers were wreathed in the vapour and, in Warner's words, "chaps were behaving very oddly – I'd tell them to do one thing and they'd head off in the other direction to do the other". He took them to see Dr Donald Hunter at the London hospital, where they were diagnosed with methylation, including Warner himself, whose hands were trembling because of the effect on his nerves.
When the Flixborough chemical plant, in Lincolnshire, exploded in 1974, Warner was appointed as the court expert. He was told to take over the site, send away the factory inspectors and police, and seal it off: "I brought in a young graduate called Rod Sylvester-Evans and put him on site in a hut, and told him, 'You live there, you sleep there and you don't let anybody in'." More information was later needed from the control room, which had been at the epicentre of the explosion, in which 28 people had died. Warner got a team of miners to tunnel into the wreck of the control room and shore it up so that Sylvester-Evans could go in and hunt for any remaining instruments that might show what had caused the explosion.
Warner was a member of the Royal Commission on Environmental Pollution (1973-76) and the Advisory Committee on Pollution of the Sea. He was also an assessor on the 1977 Windscale inquiry, examining the desirability of building a plant for the processing of nuclear fuel from the UK and abroad, at the site now known as Sellafield, in Cumbria. As treasurer of the Scientific Committee on Problems of the Environment (Scope), he spearheaded a series of definitive reports. The Environmental Consequences of a Nuclear War examined the predicted "nuclear winter" effects of a nuclear holocaust; Pathways of Artificial Radionucleotides collated data on the fallout from Chernobyl; and Radiation from Nuclear Test Explosions analysed radioactivity after every nuclear weapons test.
His work with Scope earned him the 1991 Gerard Piel award of the International Council of Scientific Unions. He was knighted in 1968, elected a fellow of the Royal Society in 1976, and was awarded both its Leverhulme medal in 1978 and Buchanan medal in 1982. A truly multi-skilled engineer, deeply involved in initiatives to unite the engineering profession both in the UK and across Europe, he was a founder fellow in 1976 of the Fellowship, now the Royal Academy, of Engineering, president of the European Foundation of Engineering Institutes (1968-71), and was involved with professional organisations for chemical, mechanical and civil engineering.
Warner was president of the British Standards Institute (1980-82), and reformed its finances by ensuring it earned at least half its income from independent sources rather than relying entirely on government funding. He was a visiting professor at University College London (1970-86), at Imperial College London (1970-78) and from 1983 onwards at Essex University. "I'm glad to say all my doctorates are honorary," he said in an interview, "it's the best way to get them I think – the easiest way!"
Warner is survived by his wife, Barbara, whom he married in 1958, and by two sons and two daughters by his first wife, Margaret, who died in 2006.
• Frederick "Ned" Edward Warner, chemical engineer, born 31 March 1910; died 3 July 2010