More on the 1977 Treaty: Exceptions and L5 ShutdownFinancial Post reported that there are exceptions.
Ottawa invokes 1977 pipelines treaty in bid to resolve Enbridge's Line 5 dispute The treaty does provide a few exceptions, including “in the event of an actual or threatened natural disaster.”
It also has some comments from environmentalist: American environmental groups said the Canadian federal government is invoking the treaty just as another aging underwater pipeline, operated by Beta Offshore Co., leaked in California and spilled 3,000 barrels of oil into the Pacific Ocean, leaving an oil slick on Orange County beaches.
“On the very day we’re seeing the effects of an oil pipeline rupture on the West Coast, Canada is seeking to increase the risk of an oil rupture in the Great Lakes by delaying the orderly shut down of Line 5,” Beth Wallace, Great Lakes conservation manager for the National Wildlife Federation, said in a statement.
“Michigan has the right and duty to protect the Great Lakes from the devastation we’re seeing in California and Canada and should be seeking alternatives instead of delays,” Wallace said.
You may want to watch the embedded video title You may want to watch the embedded video "
Shutting Line 5 will be a 'disaster', encourage imports from OPEC" starting around 4:00.