Rhone-Poulenc bought the Gloucester works in 1989. The site is in an urban area, and over the years has received several complaints about its ammonia releases.
On 1 March, roughly ten kilograms of ammonia were emitted from a gas scrubber on the site's ethylenediamine tetracetic acid plant. The release continued for up to one hour, until the company was alerted to the problem by several local complainants.
Most of the ammonia released from the EDTA plant is recovered by vacuum stripping. Secondary abatement is provided by a wet scrubber using deionised water. However, the flow alarm on the scrubber feed system had not been replaced after suffering frost damage some weeks before the incident. The meter therefore failed to detect a low level in the deionised water tank, so that the flow of water to the scrubber ceased. In addition, an ammonia monitor on the scrubber stack did not respond to the greatly increased ammonia concentrations in the emission.
Appearing before Gloucester magistrates on 29 November, Rhone-Poulenc pleaded guilty to a charge brought by HM Inspectorate of Pollution (HMIP) under section 5(1) of the Health and Safety at Work Act 1974 of failing to use the best practicable means to prevent the release. It was fined £12,000, and ordered to pay HMIP's costs of £5,400.
It is common for the courts to take account of previous convictions at the same site when setting fines. The Gloucester site had no track record of prosecutions - but the court decided to take into account Rhone-Poulenc's conviction two years ago for releases from its Avonmouth site in Bristol, which resulted in a £10,000 fine (ENDS Report 214, p 44 ). The move will be of some concern to businesses which operate a range of manufacturing sites.
In mitigation, Rhone-Poulenc said that the ammonia detector had been fitted and tested in accordance with the manufacturer's instructions. However, the instrument failed to introduce the sample properly to the ammonia detector - a fault which had not been picked up during testing because of the low routine levels of the emission. Rhone-Poulenc is now investigating alternative ammonia detection systems and has not ruled out secondary action against the instrument supplier.
Dr John Jackson, Head of HMIP's South West Region, commented after the hearing that "this case was taken because the company was clearly not in control of operations on the site; the public shouldn't be first to find out that control has been lost. I hope that this serves to demonstrate that the Inspectorate requires the very highest standard of responsible care to the environment". Rhone-Poulenc was less than thrilled by his clear reference to the Chemical Industries Association's Responsible Care programme, of which it is a prominent supporter.
The case has also raised questions over HMIP's overall prosecution policy. In recent months, it has served a large number of enforcement notices on chemical companies following a series of incidents. Several concerned management shortcomings and fairly significant unauthorised releases, notably an escape of five tonnes of vinyl chloride from ICI's Runcorn works (ENDS Reports 235, pp 6-7 and 237, pp 3-6 ).
An enforcement notice does not preclude later prosecution. But in some HMIP regions possible prosecutions for relatively serious incidents have been dropped because of a lack of resources.