Hundreds of residents were evacuated from their homes after fears a fire would trigger a huge gas explosion.

Almost 600 people living within 200 metres of a workshop at Southend Farm, in Southend Road, Billericay, will not be allowed to return to their homes until about 3.30pm today.

The residents - from an area bound by Southend Road, Grange Road, Outwood Common Road and Highfield Road - are instead seeking refuge in Mayflower Hall, Billericay School and Mayflower School.

The blaze started after a liquid petroleum gas cylinder exploded at the workshop at about 12.30pm yesterday.

More than 30 firefighters tackled the flames for at least three hours, as crowds of onlookers gathered to watch black clouds of smoke filling the sky.

The fire burnt through the roof of the 20m x 30m workshop. Residents were cleared from their homes for fear the heat could trigger an explosion of several other cylinders, containing oxygen and highly-explosive acetylene gas.

Sgt Peter Brian said: "If it exploded it could blow all the windows from the houses within 200m. The pressurised gas cylinders are next to the fire. If they heat up too much they could explode like either a bomb or a rocket.

"That's why we need the exclusion zone. It has to be for 24 hours to allow the cylinders enough time to cool to a safe level."

Assistant divisional fire officer Terry Povey said the blaze was being treated as a serious incident and would be investigated.

He said: "We do not know how it started but there is a high extent of damage. Ninety percent of the workshop was alight."

Nobody was seriously injured in the incident but a rapid response car and medics were called out.

One man was treated for smoke inhalation and minor burns and taken to Basildon Hospital.

Another man who suffered minor burns to his face and a 46-year-old woman with breathing problems were treated at the scene.

The ambulance rem-ained on standby for a further two hours. The roads were closed and bus routes were diverted from the area.

Basildon Council leader Malcolm Buckley said the authority had put an emergency plan into action and were working around the clock to help residents with essentials such as bedding and food for the night.

He said: "It's a very difficult situation for everyone involved."

Mr Buckley said the council had set up an emergency hotline for residents to call. The number is 01268 286622.