Families were evacuated from their homes today amid fears of a chemical explosion at a sewerage plant while firefighters fought a blaze in a storage barn.

Explosive cylinders of gas were caught up in the blaze at the barn, thought to be a listed building, on the Yorkshire Water Esholt works off the Harrogate Road in Apperley Bridge.

Fire crews had to get the water from the River Aire, about half a mile away to fight the flames as there was no supply on site.

The homes were just a few metres away from the fire and incident commander Allan Jones, from Odsal fire station, said there was a chance the barn contained other chemicals.

He said: "We didn't know we would find the liquid petroleum gas cylinders in the barn, but there were at least five.

"We think it could have housed other chemicals in the past and there could be pesticide in there at the moment.

"The people from the homes nearby had to be evacuated in case the situation got worse.

"We are just trying to keep the cylinders cool before removing them and we also want to stop the fire spreading to other parts of the barn, a section of the roof has already collapsed."

He said the cause of the fire was not yet known but residents claimed to have seen youngsters not from the area playing around the barns in recent weeks.

Scott Simpson, 28, was one of those told to leave their homes at about 7am. He said: "I didn't know what was going on.

"My dad, Paul, just told me to get out of the house and by the time I came down there were already other people standing around.

"The worst thing is that the barn stores the power for our homes and now we are going to be cut off for ages."

Seven crews from Bradford, Shipley, Rawdon, Bingley, Bramley and Idle were at the barn, just across the road from the water treatment works, by about 7am.