Where: Flixborough, Lincolnshire
When: 1 June 1974
An explosion at a chemical plant where a crack in a reactor was leaking cyclohexane, a bypass system ruptured resulting in vapour cloud of cyclohexane forming, leading to a large fire and explosion.
This incident led directly to the introduction of the Health and Safety at Work etc Act 1974, and the Advisory Committee on Major Hazards (ACMH) under the auspices of the newly-formed Health and Safety Executive.
Where: Seveso, Italy
When: 10 July 1976
Fatalities: No human deaths were attributed to TCCD but many individuals fell ill
A bursting disc on a chemical reactor ruptured. A cloud of vapour was seen to issue from a vent on the roof. A dense white cloud, of considerable altitude drifted offsite. Among the substances of the white cloud released was a small deposit of TCCD, a highly toxic material.
The nearby town of Seveso, located 15 miles from Milan, had some 17,000 inhabitants.
The above incidents led to the Seveso Directive, following the need for consistency throughout Europe. This Directive was largely influenced by the work carried out in the UK by the ACMH, and in turn led to the formation of the Control of Major Accident Hazards Regulations in 1984.
Where: Bhopal, India
When: 3 December 1984
Fatalities: 2,000 (approx)
Injuries: Tens of thousands
A relief valve on a storage tank containing highly toxic methyl isocyanate (MIC) lifted. A cloud of MIC gas was released which drifted onto nearby housing. The exact numbers of dead and injured are uncertain, as people have continued to die of the effects over a period of years. The severity of this accident makes it the worst recorded within the chemical industry.
Where: BP Texas City refinery, 40 miles from Houston, Texas, USA
When: 23 March 2005
The raffinate splitter in the isomerisation unit was being restarted after a shutdown. The raffinate splitter is part of the Isomerisation unit that distils chemicals for the isomerisation process. The splitter was over-filled and over-heated. Liquid subsequently filled the overhead line, and the relief valves opened. This caused excessive liquid and vapour to flow to blowdown drum and vent at top of the stack. An explosion killed 15 people and injured many others.
The US Chemical Safety Board (CSB) issued a safety recommendation in October 2005. As a result, BP commissioned research by a panel, led by former US Secretary James Baker III in October 2005. The 'BP US Refineries Independent Safety Review' Panel was established to make a thorough, independent and credible assessment of the company's five US refineries and of the company's corporate safety culture and published its report on 16 January 2007.
Although many of the issues identified by Baker were already reflected in HSE's intervention strategies, there were a number of implications for HSE's regulation across the major hazard sectors. The US reports presented a significant opportunity to push the industry to improve its process safety management, to develop site specific lagging and leading indicators of process safety performance.