Environmental campaigners have named the UK's worst polluting factories - and claim two of the worst 10 are in the North-east.

Friends of the Earth has released figures for the plants which release most cancer-causing substances into the atmosphere and names two of Teesside's major employers on its blacklist.

But the chemical companies highlighted by the campaign group, based on the Environment Agency's Pollution Inventory, claim the figures are misleading.

The study also shows that while the volume of chemicals being released by Britain's biggest factories has fallen by about 40 per cent in the last three years, the reduction on Teesside is only 18 per cent.

Teesside's top offender is ethylene dichloride producer Ineos Chlor, whose plant at Wilton emitted 408 tonnes of recognised carcinogens into the atmosphere in 2000, putting it at number five on the national list.

It's factory at Runcorn in Cheshire topped the list with 3324 tonnes.

The company refused to comment on the findings today (March 6). The site was taken over by Ineos Chlor from ICI in January 2001 and is due to close completely in July.

Chemical plant BASF, based at Seal Sands, was next in the league at number eight with an emission rate of 201 tonnes for 2000 - a 22 per cent increase for the company from 1998 to 2000.

A BASF spokesman said the figures were out-of-date. "Our figures for 2001 show that our emissions are down by 21.4 per cent. Why don't Friends of the Earth publicise that?" Mike Childs, senior pollution campaigner at Friends of the Earth, said Teesside's figures for cancer-causing pollution were disappointing compared to the rest of the country.

"If factories can make bigger cuts in pollution elsewhere why not in Teesside? We will be discussing these findings with the Environment Agency."

But factories in the area say they are committed to reducing emissions.

Chemical plant Fine Organics, based at Seal Sands, has dropped out of the top ten down to number 13 and has, from 1998 to 2000, reduced it's emissions by more than 50 per cent.

"We have an active programme in place to try to reduce emissions and are working closely with the Environment Agency," said a spokesman.

Four of the factories on the list are based at Seal Sands and three at Wilton.