Ten firecrews tackled a huge blaze for four hours in a bathroom store in Preston.
Firefighters were called to Bathroom Traders on Red Scar Industrial Estate at 7.25pm on Wednesday after reports of thick plumes of smoke coming from the building.
Reports suggested about a fifth of the warehouse was on fire when the crews arrived.
They used five jet hoses and breathing apparatus to tackle the fire, spending several hours at the scene.
Eyewitness Greg Lowde said around 200 people gathered near the store to watch the firefighters.
He said: "There was lots of black smoke coming out. It was a right spectacle."
Police also attended the incident, and the fire was brought under control at around 11.30pm.
Businesses on the industrial estate were evacuated and residents in the Franklands Drive area of Ribbleton were advised to stay inside their homes with their doors and windows closed.
Group manager Tony Crook, of Lancashire Fire and Rescue Service, said: "On one of the hottest nights of the year, our crews did a great job of surrounding the fire to get it under control and were able to keep damage to the building to a minimum, stopping it spreading to neighbouring premises.
"We have kept a number of fire engines and crews in place at the unit overnight to continue to damp down and they will remain in place until we are completely happy that there is no residual heat or anything that could cause further problems."
Crews from Fleetwood and Blackpool were still at the scene this morning damping down and ensuring the fire did not re-ignite.
Preston fire station were also called to the premises next door after smoke from the fire set off their alarms. But nothing had been damaged.
Investigations will be carried out today to try and establish what caused the fire.
It comes two years after a huge chemical fire at the Veolia Cleanaway site on the Red Scar estate.
>> Vote in our latest web polli-map: All the news from around the North West on our interactive map