Worshippers arriving at a city centre church yesterday were turned away after a gas cloud billowed out of a dye company's premises following a chemical spillage.

Police are investigating a break-in at the Wilkinson & Scott building in Nelson Street, Bradford. It is thought the burglar may have deliberately caused the spillage.

Firefighters from nearby Bradford Fire Station were called after a member of the public raised the alarm at 9.45am.

Station Officer Phillip Whitaker said two firemen wearing chemical protection suits and breathing apparatus went into the premises and found liquid coming out of two large containers.

He said: "Each contained about a ton of liquid. One was formic acid, the other a 32 per cent ammonia solution. They were coming out from the open valves.

"They were mixing together, neutralising each other and forming this gas. When we arrived there was quite a large cloud of smoke-like white/grey gas which was enveloping the premises and sweeping across Nelson Street so you couldn't see across the road.

"But there was quite a strong wind and it dispersed very quickly.

"It appears that someone had broken into the premises to steal diesel from a vehicle in the yard and maliciously opened the valves while they were there.

"There have been no reports of anyone suffering ill effects. It was lucky one liquid was acid and the other alkali. They neutralised each other.''

Firefighters closed the containers' valves and called in company experts to clear up the spilt chemicals.

During the incident firefighters and police closed off the section of Nelson Street between the Interchange and fire station. People arriving at a nearby church for Sunday morning worship were moved away from the area.

Acting Insp Keith Gilert, of Bradford Central Police, said officers were investigating a reported break-in.