The Environment Agency said it had acted after concerns that the Parkwood site has been accepting hazardous waste for which it is no longer licensed.

A spokesman for Parkwood's operators, Viridor, said they were bewildered and frustrated by the agency's action.

Manager Dan Cooke said they had been investigated on three occasions and had not received any adverse comments.

'No significant risk'

The company said it had been following Environment Agency- approved procedures since new regulations came into force in 2004 which banned the disposal of hazardous waste in the same place as non-hazardous waste.

Mr Cooke said the three investigations had taken place since January.

They submitted their full monitoring regime on each occasion, he added.

"We have cooperated fully and have repeatedly attempted to meet with officers to discuss their concerns," he said.

"Viridor calls on the Environment Agency to work with us on this matter so that the local community can be reassured there is no significant risk to health or the environment and that we are not accepting inappropriate wastes."