A major investigation is under way after a huge fire ripped through a waste disposal unit, causing explosions.

Six fire engines and around 45 firefighters rushed to TCS Waste Ltd, on Heys Lane in Great Harwood, early on Sunday, August 2.

Propane gas cylinders were also inside the building, however fortunately they did not ignite, while road closures were put in place for most of the day.

Lancashire Fire and Rescue Service (LFRS) also declared a chemical incident alert ‘Operation Merlin’ after plumes of thick black smoke were seen coming from the building.

Local authorities and organisations including Air Traffic Control were put on alert and firefighters were forced to pull back to a safe distance and tackle the blaze using an aerial ladder platform.

Explosions were also heard coming from the 40m by 20m building, which were later found to be tyres on a skip wagon.

LFRS said they were called shortly after 6.30am and believe the cause of the fire is accidental but an investigation will now be launched to determine the cause.

Richard Edney, spokesperson for LFRS, said: “When the crews got there the fire was going through the roof. We sent more fire engines to the scene so there were six fire engines, an aerial ladder platform, and a hazardous materials unit from Burnley.

“At one point there were exploding tyres caused by the heat so the crews had to be removed to a safe distance and they used the aerial ladder platform to attack the fire.

“There was a lot of thick black smoke so Operation Merlin was declared which notifies other local relevant authorities and organisations including air traffic.

“By 11am the crews had got on top of the fire and Operation Merlin was stood down. The crews remained at the scene until about 9pm and then periodically went through the night to inspect it.

“We are working with the owner and fire investigation team to work out exactly what the cause of the fire was.

“There was a number of road closures and community protection manager Steve Morgan wants to thank the public for their cooperation.”

Lancashire Police confirmed they were alerted at 6.35am and cordons were put in place around the scene on Alan Ramsbottom Way, Hyndburn Road, Wood Street and the junction of Spring Street and Stanley Way.