Thousands of fish died and thousands more were damaged by agricultural chemicals that leaked into the River Nene in Peterborough, magistrates heard on Tuesday 26 February.

Some of them were bleached and others leapt from the water and died along the affected 50km stretch of water. Chemical manufacturer and packaging company Safapac pleaded guilty at Peterborough Magistrates’ Court to causing the pollution on 18 June 2012 and claimed vandals damaged containers allowing 5,000 litres of three chemicals to get into drains. The case has been sent to the crown court for sentence as magistrates felt their sentencing powers were insufficient. Mrs Anne-Lise McDonald, prosecutor for the Environment Agency, told magistrates that the company reported the spill to them on a day when they had also taken 15 calls from people about distressed fish in the river.

Investigators linked the two incidents. Drainage plans held by the company at their Orton Southgate site and initially shown to environment officers showed a drain on site led to a foul sewer. Further investigation by the company identified that it was, in fact, a surface water drain which discharged to the river.

All three chemicals, an insecticide, a fungicide and a disinfectant, are known to be very toxic to aquatic organisms and can cause burns, drowsiness or dizziness to people. The effect on the River Nene was seen as far as Wisbech and cockle fishing in The Wash was quarantined and closed 19-21 June by the regulatory authority. Mrs McDonald told the court that a survey at this time showed a ‘clear and substantial’ impact on all living things in the Orton Brook and River Nene for at least 14.7km.

The pollution had an impact along 46km of the brook and river. Peterborough and District Angling Association had to cancel fishing matches and members also cancelled because of the pollution, costing the club £928. Two cockle fishermen claimed they lost more than £10,000. The total cost to the members of the Greater Wash Fishing Industries Group was estimated to be £216,772 as a result of the pollution.

Mrs McDonald told magistrates that the pollution could have been prevented if the chemicals had been stored securely. “Bulk containers containing the chemicals were stored in external bunkers near to the road. There was no bunding and no secondary containment in case of spills,” she said. “There was an open drain in the storage area and another just outside.” She told the court that Safapac’s high level risk assessment had failed to identify vandalism as a risk but on the morning of the pollution staff had arrived at work to find taps on the storage containers had been opened and a ladder had been used to get in. Police records showed that the company had made five reports of criminal or anti-social behaviour directed at the company or in the immediate area since 2010 involving youths causing damage to or trespassing on Safapac’s property or metal theft.

A Safapac manager told investigating environment officers that staff had closed an emergency valve within 15 minutes of discovering shattered valve caps and police and the Environment Agency notified. He said CCTV at the site was not recording at the time and the ladder used to get in had been stored on top of a container at the site. Chemicals are now stored in locked shipping containers.

After the hearing Environment Agency officer Adam Shamma said: “This case should serve as a reminder to companies who handle chemicals to ensure their storage arrangements are adequate. Safapac would have prevented this incident if their chemicals had been stored in a secure, bunded area. “Advice and guidance on pollution prevention is available on the Environment Agency’s website.”