An explosion and fire at a chemical-products plant briefly prompted concern on Wednesday that parts of Granby, Que., might need to be evacuated.
Authorities began an evacuation plan while testing the air quality following an incident at the Aldex Chemicals plant.
Firefighters say that after tests concluded the air was non-toxic, the plan was called off and residents were allowed to spend the night in their homes.
The fire left a thick, dark cloud of smoke hovering around the southeastern Quebec city.
The building, located in an industrial park, was completely in flames and the dark clouds were shifting toward the city.
Within hours, firefighters said the blaze was well-contained but would probably not be extinguished before Thursday morning.
Authorities established a one-kilometre security perimeter in the area and did evacuate some neighbouring businesses.
Police spokesman Guy Rousseau says no one was injured in the explosion at the plant in the community of about 63,000 residents, about 80 kilometres east of Montreal.
"There were people in the plant when the explosion occurred but now there's no people there and we have confirmation that nobody's injured," Rosseau said.
The company website says Aldex was founded in 1976 and makes cation resins, used in various decontamination procedures. The local newspaper, La Voix de L'Est, reported that the plant has about a dozen employees.
Other media reports said this was not the first fire at the plant.
The cause of the blast isn't known.