TELEPHONE lines at an oil refinery were jammed yesterday after worried residents living nearby woke to find a light scattering of white powder on the streets.

Locals in Grangemouth contacted officials at the BP Oil refinery after discovering roof-tops, roads, cars, and trees, covered by a fine dust.

However, bosses at the plant stressed yesterday that the powder was not toxic and posed no threat to the public and offered a free car wash to motorists.

The cloud of dust was released shortly after 7am when the refinery's catalytic cracking unit, which produces petrol, unexpectedly shut down after it detected a problem.

It was carried southwards by a light wind before scattering a fine layer of sand-like powder over a number of streets in the town centre.

Environmental officials at Falkirk Council were contacted along with the police and the Scottish Environmental Protection Agency (SEPA) in a bid to help clean up the fallout.

Wilma Hutton, 33, who lives in South Marshall Street, said she had become worried after seeing the powder covering all the cars.

Mrs Hutton said: ''The cars and the street were covered in white stuff. When we went to have a closer look we saw it was some form of powder and we were slightly concerned.''

Another resident from the street said he was furious the accident was allowed to happen on his doorstep.

He said: ''I have washed my car four times now and the sand is still there. It will definitely mark my car and I am livid.

''We did not know what was going on and nobody told us anything.''

Yesterday officials from the plant stressed the powder posed no threat to the public and offered free car wash vouchers to affected residents.

A BP spokesman said: ''The phones have been quite busy with people wanting to know if the powder is dangerous. We are advising people to wash their cars as soon as possible and we have organised a team of road sweepers to clean up the streets."

Peter Duncan, who works in the town's Grange Service Station, said he had been inundated by people looking to use the carwash to remove the powder from their vehicles.

He explained: ''I have had people coming in all morning and it's been a bit strange seeing all the cars covered in the powder.''

Yesterday Eva Cahill, of SEPA, added further tests would be carried out to ensure the dust posed no risk to the townsfolk.

She said: ''We have taken all necessary precautions and it does not appear to be harmful but we are taking samples to be tested.

''We will be going out again to try and find out what caused the incident.''