Bolton Crown Court has fined United Utilities £600,000 and its contractor, KMI+, £333,000 for polluting a brook with sodium hypochlorite, killing almost all aquatic organisms.
The court was told that KMI+, a joint venture between four companies – Kier Infrastructure and Overseas, J Murphy & Sons, Interserve and Mouchel – was contracted to carry out improvements at Wayoh water treatment works at Turton Bottoms, north of Bolton. On 4 December 2013, the contractors removed and emptied a tank used to store sodium hypochlorite in 10% solution.
Richard Bradley, prosecuting for the Environment Agency, said that instead of pumping or siphoning the 300 litres of remaining liquid out of the vessel, water from a hosepipe was fed into the tank to dilute the sodium hypochlorite before it was allowed to overflow into a bunded area, which was left unsupervised for more than 15 hours.
Bradley said the contractors and United Utilities had assumed the liquid would flow through drainage pipes to another tank, but they did not carry out a risk assessment and neither company had surveyed the drainage system. Some of the pipework was broken, leading to the solution spilling into Bradshaw Brook. ‘Although it was diluted, once in the watercourse it was highly toxic,’ he said.
Sodium hypochlorite is used in water purification and is also the principal ingredient of household bleach. It is very corrosive and highly toxic to aquatic organisms.
On 4 December, a member of the public contacted the agency after spotting dead fish. Agency officers found that a 1.7 km stretch of the brook leading towards Jumbles Reservoir was so badly polluted nearly all aquatic life was killed, including fish, shrimp and earthworms.
Up to 900 dead fish were recovered, including brown trout, loaches and bullheads, but the agency said the number killed was likely to have been much greater. In June 2014, United Utilities paid for the brook to be restocked with native fish from the downstream section.
The Honorary Recorder of Bolton, Judge Timothy Clayson, said the incident had arisen through senior management failings to ensure a proper system and procedures were in place. Gordon Whitaker, environment manager at the agency, described it as avoidable and blamed negligence by both parties.
United Utilities referred to the incident in its 2014 corporate responsibility report: ‘We take this kind of incident very seriously and we have undertaken improvements both at the site concerned and other sites across the business to ensure we prevent this type of incident again.’
United Utilities and KMI+, which both pleaded guilty, were also ordered by the court to pay costs of £19,090 and £26,712 respectively.
