A blaze at a Somerset plant nursery sparked a pollution alert after bags of weed killer and fertiliser caught fire.
Environment Agency officers joined fire crews at the Rocky Mountain nursery in Old Frome Road, Maesbury, on Wednesday night after fire started in a barn.
A man was treated at the scene for breathing difficulties after toxic fumes filled the air and residents were advised to keep windows shut.
There were also fears the chemicals had contaminated a local stream.
Fire-fighting operations were hampered by the risk of explosion from acetylene cylinders at the site.
Investigations into the cause of the fire could not start till Thursday morning as crews remained on site to cool the cylinders down.