BBC NEWS | UK | Smoke cloud spreading over South: "Smoke cloud spreading over South
A cloud of black smoke is spreading over a large area of southern England after a series of explosions at an oil depot in Hemel Hempstead.
Although winds are light, smoke is drifting towards Reading and Swindon, the Met Office has said.
North-westerly winds on the surface are extremely light, but higher up north-easterly winds are stronger.
The smoke, which is understood to be of low toxicity, could make people cough and feel nauseous, police have said.
The Met Office said the smoke could reach Southampton by Sunday night.
Smoke has risen very high with aircraft reporting it at an altitude of 9,000 feet.
There are already reports of some smoke in Hampshire.
Peter Kidds, a weather forecaster for the Met Office, said sooty particles could fall to the earth as the smoke cools.
They would contain pollutants, not in high concentrations, but enough to 'be of concern'.
He added that for at least 24 hours there was not expected to be any change in the weather, including wind directions, that would affect the smoke cloud.
Howard Borkett-Jones, medical director at Hemel Hempstead General Hospital advised those who felt the effects of smoke to 'reduce their exposure to it by keeping all their doors and windows closed'.
He said although the smoke was of 'low toxicity', hospital staff were prepared for dealing with some respiratory problems.
'We understand that in general terms it is of low toxicity but people might experience some irritation to their respiratory system, some slight tightness in the chest because of irritation and coughing as a result of exposure to noxious chemicals in the atmosphere,' he said.
He added if people continue to feel unwell they should contact NHS Direct or their GP's out of hours service.
A police spokesman said people should keep out of the smoke and to keep doors and windows shut.
'This cloud, not least because it contains heavy smoke, is an irritant, and will certainly make people who inhale it potentially cough, potentially irritate the eyes and potentially feel nauseous.
'Our very strong advice is that people must keep out of the plume of smoke.'
He added people whose windows have been blown out should evacuate to 'somewhere safer'.
People experiencing symptoms of smoke inhalation can contact NHS Direct on 0845 4647.
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