A 200m cordon remains in place around Wyre Waste on Jameson Road in Fleetwood after police launched an investigation into the fire, which ripped through the building on Boxing Day evening.

Fire crews have drafted in long-distance jets to cool down the canisters, which are at risk of exploding as the premises smoulder.

John Taylor, spokesman for Lancashire Fire and Rescue, said: "The emergency exclusion zone is still in place, as we still have fire crews spraying water at the site from a distance.

"Although it is an inconvenience to have this, we are not being over- cautious.

"Some of the gas canisters contain acetylene, which can retain hot spots even when they've cooled down and can have a bomb-like effect if they explode."

The North West Environment Agency has now been drafted in to deal with the incident.

Staff are monitoring the site as it poses a risk of air and water pollution.

Firefighters are keeping a distance as they spray the building using a specialised high-volume pump drafted in from Burnley for fires involving gas.

Mr Taylor added: "Police and fire authorities have not been able to investigate the fire properly yet, as it is too dangerous to venture too near the building.

"It is still smouldering and there is a risk of gas canisters exploding, which would be extremely dangerous. There are 15 fire personnel, two fire engines and the high-volume water pump and they will remain until there is no risk of explosion."

Graham Miller, environment officer for the North West Environment Agency, added: "Our main role at the Wyre Waste site is to assess pollution damage.

"We have been down to the building as there was a risk of air pollution, caused by the fumes, and also possible inconvenience caused to neighbours by the long-distance jets, which could spray nearby properties.

"So far we have found very little damage and we hope it will stay this way."

Police launched an investigation into the blaze after officers patrolling the site saw smoke and raised the alarm at around 8.30pm on Boxing Day.

Lancashire Police confirmed there had been reports of a break-in on Boxing Day evening but because of the risk of explosion they have been unable to conduct any further investigations.

A spokesman for Lancashire Police said: "Since we confirmed there had been reports of a break-in, we have been unable to access the building to make any further investigations, as the emergency exclusion zone is still in place.

"However, we hope to have some answers later today."

The metal-framed warehouse is used to store household waste and is owned by Singleton man Andrew Park.

The land the site is on is owned by James Parr, who is also the boss of Farmer Parr's Animal World.