A CHEMICAL leak alarmed local residents as it covered houses and roads in a fine white dust.

A giant cloud of white powder escaped from Runcorn's EVC plant at 7am on Sunday morning.

It drifted over the A577 Weston Expressway and homes in nearby Weston Village.

Worried residents followed advice to stay indoors and keep windows and doors closed as a precaution.

Anne Ryder, of Weston Road, whose home overlooks the plant, said: "I went out to walk the dog and noticed a thick white cloud.

"The cloud disappeared when it started raining. In Weston, we are used to incidents like this but it is worrying."

EVC reassured the local community there was nothing to worry about.

An EVC spokesman, said: "There was a pressure release on a PVC plastic production vessel which resulted in the emission of some PVC polymer and VC monomer.

"The VC monomer dispersed rapidly and posed no hazard.

"PVC polymer is a fine, inert white powder and a quantity of this powder was visible immediately following the incident on the A557 Expressway nearby.

"This powder poses no threat to the public or the environment. The rain will have washed most of this powder away."

EVC said a full internal investigation into the circumstances leading to the incident is now being carried out and the company is co-operating with the relevant authorities.

Firefighters confirmed that half a ton of PVC powder had escaped.

Halton Cllr Stan Hill, executive board member for the environment, said: "This is quite worrying. It shouldn't be escaping at all. I will be making inquiries and asking for a full report of the incident."