A Lancashire firm was evacuated and fire crews called after a chemical reaction created hazardous fumes.
Two fire engines, including a crew from Chorley, attended the incident on Market Street, Adlington in the early hours of Saturday, October 14.
A chemical reaction within a storage hopper caused the problem at the commercial property.
A fire service statement said: "Firefighters equipped with breathing apparatus used four dry powder extinguishers and fire blankets, and moved the chemical out of the building to dampen down and allow ventilation of the fumes.
"Staff were evacuated and all water run off was contained within interceptors located on the site."