EXCLUSIVE

THE US Navy has finally caved in to demands for help in dealing with mystery canisters found during the dredging of the former Polaris nuclear missile submarine base on the Holy Loch.

About 30 containers, which could contain anything from gas to extremely toxic chemicals, have been landed in the first stage of the mammoth underwater clean-up operation which followed the navy's pull-out.

The Americans had effectively washed their hands of any responsibility for the environmental legacy of their 30-year tenancy in Scotland which ended in 1992. They said any materials found were no longer their responsibility.

However, after repeated re-quests from the British authorities for aid in identifying the contents of the canisters, they have agreed to fly in military experts to help with their disposal.

The multi-million pound salvage operation to clear the loch bed off Dunoon began earlier this year. Using an electro-magnetic crane aboard the barge Molly McGill, teams of workers pulled up hundreds of tons of material including live munitions, broken pipes, cable, old hand tools, and, the largest item so far found, a submarine fin.

Mr John Beveridge, director of the Scottish Environmental Protection Agency's (Sepa) West Region, said the authorities were virtually helpless because all the original markings on the canisters had washed off or been eroded.

''Normally canisters are full of things like oxy-acetylene but, if somebody starts to tamper with them without knowing what is inside, they could explode or leak chemicals.

''When the US Navy left, they just handed everything over to the British Government and said 'we're gone'. There has been no help from them whatsoever. Now, the navy has agreed to fly somebody over to have a look at them so we can work out the correct approach.''

He added that the clear-up has ''just started. There has literally been hundreds of tons already cleared and the more they dredge up the more they will find there.''

Most of the scrap is believed to have been dumped over the side or have fallen off the floating complex that formed the British base for American submarines.

The Ministry of Defence and Sepa believe that despite the area's nuclear link, the sea-bed and six-metre high piles of scrap contain very low levels of radioactivity.

Mr Kevin Dunion, director of Friends of the Earth Scotland, said he was delighted the Americans were finally acting because of the mixture of materials. ''If different things corrode they could react together.

''Even if the Americans didn't have a legal responsibility to help clean up the mess they left behind, they did have a moral responsibility. We argued that some kind of inventory should have been kept by the US Naval forces instead of them just dumping things willy-nilly.''