Major hazards — Should they be prevented at all costs?

Should industry be allowed to build a plant where a major disaster of the Flixborough type is possible? On the other hand should a company sacrifice the business opportunity whereby jobs are created, our quality of life is enhanced by a useful product, wealth is generated upon which the continuing growth and prosperity of the company depends and from which the money for social services and other forms of Government spending is derived? Phrases like “the risks have been minimised”, “as safe as is humanly possible” and “designed to best engineering standards” are often used to answer the first question in the affirmative.

This paper describes a method of assessing the risks which avoids the need to rely on such subjective and widely variable judgements. It shows with the aid of a hypothetical plant as an example, how risks can be assessed in quantitative terms and how the cost of both the incident and the protection against it can be balanced to give a practical and consistent interpretation to the phrase “as far as is reasonably practicable”. It also discusses some of the problems which this approach leads to.