Chemical manufacturer Scott Bader has been fined £10,000 and ordered to pay £7,656 costs after xylene leaked undetected from its Wollaston Hall site near Wellingborough.

The chemical, a hydrocarbon, leaked into an Anglian Water sewer via a surface water drain after pressure forced the xylene mixed with water from corroded pipe-work and into a bund which did not contain it, Wellingborough Magistrates’ Court heard last Thursday.

Mrs Miriam Tordoff, prosecuting for the Environment Agency, told the court that the company held an environmental permit which set a limit for an emission of xylene into the sewer of 100 parts per million. The permit also says there should be no solvent layer or droplets visible on the surface of the water.

On 9 April after complaints of strong smells from staff at a nearby factory, an Anglian Water inspection found that the sewer on site was ‘visibly contaminated with an oily substance’, she said. Analysis of a sample subsequently showed xylene was present at a concentration of about 3,900 parts per million. Scott Bader estimated that about 50 litres of the chemical mix had leaked into the bund, but said that they estimated that only half a litre went into the sewer.

Scott Bader activated a valve to stop any further chemical getting into the sewer downstream.

Fined for permit breaches

Although there had been no adverse environmental impact, the company had breached its permit limit and pleaded guilty at Wellingborough Magistrates’ Court to a charge relating to that breach.

Mrs Tordoff explained that over time acidic vapours from one of the reactor vessels at the chemical plant had been escaping through a faulty butterfly valve into a fusion tank which was not designed to cope with them. The valve was supposed to isolate the reactor system from the fusion system. The vapours corroded a section of pipe creating a hole of 5-10mm diameter.

When the reactor vessel was pressurised, the xylene/water mix was forced out through the hole into the bund. The sealant on the bund wall had degraded and Scott Bader accepted that the nature of the block-work of the bund wall clearly allowed the liquid to seep through. The surface water drain was directly adjacent to the bund wall.

Scott Bader admitted being in breach of its permit because of a series of errors or failings. An employee who saw the leak from the pipework did not report it as he believed it to be the contents of the fusion tank which are not very dangerous and would not constitute a high level incident.

The Environment Agency also highlighted poor management systems for inspecting the integrity of bunds which are a key protection system and the failure to identify the risk of not isolating the two systems properly.

The company has since removed the Fusion process equipment, repaired the bund and has planned improvements to the surface water drainage system on the site.

Scott Bader is a chemical manufacturing business making a large range of chemical bases for products such as paint, varnishes, resins, adhesives and speciality coatings.

After the hearing Environment Agency officer Kevin Burton said: “This incident has highlighted the importance for companies to thoroughly assess the risks from all of their activities. It is also vitally important that key environmental protection systems such as bunds are inspected and maintained to the highest standard, ready to contain leaks or spillage at any time.”

Anglian Water also prosecuted the company for breach of its trade effluent consent.