About 10 firefighters were taken to hospital in Leicester after a blaze destroyed an adhesives plant in Corby.
A spokeswoman for Leicestershire Fire and Rescue Service said they were being detained as a precautionary measure because chemicals had been involved.
But she added none of the firefighters who are from the Market Harborough area were showing any signs of illness.
They had been responding to a fire at Caswell Adhesives on Earlstrees Industrial Estate in Corby on Tuesday.
A large part of the town was left engulfed in thick smoke, and many nearby businesses and residents were told to keep doors and windows shut.
More than 60 firefighters tackled the flames and two people were taken to hospital for smoke inhalation.
The firefighters taken to hospital were expected to remain there for between 24 and 48 hours for precautionary checks.
An investigation was due to be carried out into the cause of the fire once inspectors believed it was safe to go onto the site.
^ Back to top | BBC Sport Home | BBC Homepage | Contact us | Help | ©
~RS~q~RS~~RS~z~RS~11~RS~)