Canadian Pacific Railway is trying to determine what caused nine freight cars to fall off the rails in Canmore early Monday morning, spokesperson Breanne Feigel says.
Two of the cars contained butane while the others carried glycol, an ingredient used in antifreeze and windshield washer fluid, Feigel told CBC News.
One of the cars carrying glycol had a minor leak, which does not pose any health risk, she said.
Two schools and several nearby businesses were evacuated as a precaution, but the evacuation order was lifted later Monday morning.
Parts of the mountain town, 90 kilometres west of Calgary, were also cordoned off while police determined the contents of the derailed cars.