Nearly four tons of sodium hydrosulfite caught fire Wednesday afternoon at a product storage and distribution facility in southern Quebec.
City officials in Tres-Rivieres issued a shelter-in-place order for city residents within an 800-meter radius of the burning facility. As of midnight Wednesday, the fire was still in progress.
“A fire is underway at the Somavrac factory located in the Gilles-Beaudoin industrial park in the Sainte-Marguerite sector in Tres-Rivieres,” a notice on Facebook states.
At about 2:10 p.m., fire broke out near several containers of sodium hydrosulfite, also known as sodium dithionite. In industry, it is used in dyeing processes, water treatment and gas purification.
At temperature higher than 194 degrees Fahrenheit or if exposed to water, it decomposes into sodium sulfate and sulfur dioxide gas. The gas is toxic only in high concentrations.