The high-tech appliance, which is being trialled in Blackburn and features a pointed ‘stinger’, is capable of piercing roofing slates, tiles, and panels to tackle blazes from above.
It was called out to Dawson Lane in Whittle-le-Woods at 10.18pm to pump 3,000 litres of water into the huge mound as a precaution.
“They were not sure if it was a fire or just steaming off,” a spokesman for the Lancashire Fire and Rescue Service said.
The building was left open and was re-inspected this morning, when it became clear following further tests the rubbish had been decomposing and not burning as first feared.
The Stinger, which replaced a regular engine at Blackburn last November, will move onto Burnley for six months later this year, but will continue to be used at major incidents across the county, and could also end up in Preston.