THIRTEEN people were taken to hospital with suspected inhalation difficulties after a chemical paint leak at an information technology distribution firm in Altham.
Three ambulances and four engines were alerted after reports of an incident at Exertis Micro-P, in Shorten Brook Way.
Firefighters were told that workers had been affected by a chemical-based paint during roof repairs.
Richard Edney, of Lancashire Fire and Rescue Service, said: “Two firefighters wearing breathing apparatus used two portable ventilation units to clear the area of fumes.”
A North West Ambulance Service spokesman said that three ambulances and a hazardous materials response team was sent to the scene.
Thirteen patients were taken to the Royal Blackburn Hospital with inhalation issues and two extra passenger transport ambulances were drafted in. Hospital officials were unable to confirm whether the patients had been allowed home last night.