[Telegraph.co.uk] Parts of Cumbria are still affected by the radioactive fallout from the fire at the Windscale half a century ago, experts said yesterday.

The 1957 accident at Windscale pile one, a military reactor on the Sellafield site used to make plutonium for bombs, released a radioactive cloud that spread contamination over England and Wales, with hotspots on the western coast of Cumbria.

It is still the West’s worst nuclear accident. The fallout could be detected in mainland Europe and, even though it was small in comparison with that ejected by the Chernobyl explosion 20 years ago, it was a much greater threat to life than the partial meltdown at Three Mile Island in the United States.

One isotope, caesium-137, from the Windscale fire can still be detected in a few areas of Cumbria, along with that from Chernobyl and nuclear weapons testing carried out in the 1960s, said Dr Jim Smith of the Centre for Ecology and Hydrology, Dorchester.

In a relatively small upland area to the south-east of the Windscale site, deposition from the 1957 accident contributes as much as 60 per cent of the total caesium-137, his colleague, Simon Wright, said.

In most of the west of Cumbria, where levels are highest, caesium-137 from the Chernobyl accident dominates. In the east of the county, nuclear weapons testing fallout from the early 1960s contributes most to the caesium-137 in soil.

There are still restrictions on nine of the 1,670 farms in Cumbria that were originally imposed in June 1986 following the Chernobyl accident.

“From our studies in Cumbria it could be another 10 years before all the farms are clear – though even now very few sheep are in excess of the limit above which they cannot enter the human food chain,” said Dr Smith.

The older sources of caesium-137 in the environment are now contributing to the need for continued restrictions in west Cumbria but the county is still less radioactive than Cornwall, where there are much higher natural levels because of radon gas from granitic rocks.