A Penryn based recycling firm has been fined £2,500 after waste chemical pollutants killed fish in a nearby river.

Magistrates in Camborne heard that Advanced Oxidation Ltd, on Kernick Industrial Estate, poured a cocktail of toxic chemicals into the Penryn River by mistake.

The case was brought by the Environment Agency after reports of strong chemical smells, foam in the water and dead fish last April.

Later the Environment Agency traced back to a culvert in the estate and later traced it back to a research and development company which is part of Advanced Oxidation.

The company was fined £2,500 and also ordered to pay costs of £515 after pleading guilty to three offences under the Environmental Protection Act 1990 and Water Resources Act, including causing poisonous, noxious or polluting matter to enter controlled waters and disposing of controlled waste in a manner likely to cause pollution.

Redwynn Sterry, of the Environment Agency, said that the spill was "entirely foreseeable and preventable" and that "no thought was given by the company or manager to the risk their activities posed."

Magistrates heard that employee Simon Drew went off to answer a telephone, leaving waste draining into a high-tech recycling on April 24.

However the complex mechanisms for securing the tank were not properly shut and a lid "slipped" causing more than 500 litres of raw untreated waste, including caustic phenol, to escape.

The toxic chemicals, some of which can cause severe burns, convulsions, lung damage and even death, got into the stream and polluted two kilometres of the water killing eels and fish.

Prosecutor Judith Constable said that there had been several reports from members of the public about the spill and that the pollution was still visible three days later.

Advanced Oxidation's managing director Paul Cullen said he had not informed the Environment Agency about the spill because he thought the drains into which the waste ran led straight into the sewer.

An investigation found the firm's emergency spill kit to be "woefully inadequate" for the task and at one point staff went to buy cat litter to act as an absorber.

Mark Howard, defending, said the company was a "cutting edge" outfit which was developing new methods of treating hazardous liquid waste using an advanced oxidation process.

Since the spill their emergency regime had been tightened up and a full-time administrator had been employed to monitor proceedings.

Mr Howard added that it was an "isolated incident" which was the result of a "series of circumstances."

The court heard the chemical was hosed down to dilute it, but this only sent it down the drains and into the river.

Site manger Paul Beardsmore had been interviewed and cautioned by the police in relation to the spill.