Residents near Montreal were urged Saturday to stay in their homes after the Kronos chemical-producing plant let a potentially toxic gas into the air. About 15 houses closest to the plant in Varennes, Quebec, were evacuated, Global News reported. The leak continued Saturday afternoon, as officials had yet to find the source. It was due to an equipment failure.

Starting at about 10 a.m., more than 40 tons of titanium tetrachloride spilled out of the company's South Shore factory. The chemical, which is used to make titanium metal, breaks down with water and can become harmful upon contact with humid air, according to the Weather Network. It can irritate people’s eyes and skin, constrict parts of the upper respiratory tract and damage the cornea.

Residents Saturday could see and smell the gas, which CBC News reported took the form of a big white cloud. In addition to evacuating homes, authorities began testing the air and shut down Highway 132 in both directions between Montée Picardie and Montée de la Baronnie. They were concerned high winds would spread the gas from Varennes to Lachenaie or Riviere des Prairies, the Chronicle Bulletin reported, though they insisted people who lived more than 400 meters (0.2 miles) from the factory were safe. People could smell the gas as far away as Verchères and Repentigny -- about 15 and 30 minutes from the site, respectively.

The measures were precautionary and aimed at ensuring “the safety of people and protection of the environment,” the provincial environment department said in a news release. Nobody has reported injuries so far, and emergency officials were continuing to work to find and fix the leak. Local residents were instructed to stay inside until further notice.