Authorities issued emergency orders to stay away from the downtown area because of flooding brought on by heavy rains. Enbridge Energy said this week it suspected floodwaters disrupted an underground oil pipeline, resulting in the release of about 750 barrels of heavy tar sands oil.
Corporate offices for many energy companies were closed as a result of the emergency orders. The National Energy Board, which has headquarters in Calgary, said its offices would be open on a limited basis starting Thursday but will not open completely until Tuesday.
Enbridge this week said it was able to get response teams to the site of the spill near Fort McMurray.
Canadian Natural Resources Minister Joe Oliver, meanwhile, said the federal government is requiring pipeline operators to have the financial capability to respond to any incidents like the Enbridge spill.
Oliver said Wednesday companies are expected to have at least $1 billion on hand for emergency operations.
"Our government is developing our natural resources in a way that enhances jobs, long-term prosperity and environmental protection," he said in a statement.