This week’s escalation of American pipeline setbacks is heightening concerns among Canadian oil producers who export almost all of their crude to the U.S. Alex Pourbaix, the chief executive officer of Cenovus Energy Inc., called a ruling temporarily shutting down the Dakota Access pipeline on Monday “pretty disturbing” in its implications that existing conduits may now be at risk. His concerns were echoed by the CEOs of Suncor Energy Inc. and Exxon Mobil Corp.’s Imperial Oil Ltd.

On Sunday, U.S. power company Dominion Energy Inc. and partner Duke Energy Corp. said they’re killing the controversial Atlantic Coast gas pipeline, citing ongoing delays and uncertainty on costs. The next day, a U.S. district court ruled that Energy Transfer LP’s Dakota Access pipeline will have to shut down in about a month because a federal permit for the line fell short of environmental requirements. Later that day, the U.S. Supreme Court left in force a lower court order that blocks construction on TC Energy Corp.’s Keystone XL pipeline.

Similarly, Canadian producers have also had to deal with a temporary shutdown of Enbridge’s Line 5, which helps carry crude and natural gas liquids to refineries in eastern Canada. A Michigan judge ordered the full line shut down last month after damage was found on a portion of it running through the Great Lakes. While Enbridge was allowed to restart the line a week later, Michigan’s governor and attorney general still are working to force the line to cease operations.

Imperial has been looking at using ships and rail to supply Ontario refineries in case the line has an extended shutdown, CEO Brad Corson said Tuesday at the TD Securities conference.