The UK is set to take back more than 1,400 tonnes of toxic waste that was found in Brazil, the Environment Agency said today.
The Agency said it was aware that over 80 containers of waste had allegedly been illegally exported from the UK to Brazil.
Plans are now being made to bring the rubbish back, although the process could take a number of weeks, it said.
Those responsible could face prosecution, the Agency warned.
Head of waste Liz Parks said the waste was currently being held by Brazilian authorities.
She told the BBC: "They haven't yet released it, as far as I'm aware. But arrangements are being made for that to happen. And it will take a number of weeks for the waste to be returned."
The Environment Agency has launched an investigation into the case and to determine if an offence has been committed.
A spokesman said: "The UK is completely against illegal trade of any kind and has taken a strong global lead to stamp out the illegal trade in waste in order to protect the environment and human health.
"Where the Environment Agency detects or is made aware of the illegal export of waste, it works with all relevant partner authorities to ensure the environmentally sound management of any illegal shipments - including the possible return of wastes to UK.
"If any company is found to have contravened the strict controls on the export of waste as set out by the Basel Convention, the Environment Agency will not hesitate to take enforcement action."