Canada could be on an emissions collision course with the U.S.

Canada could find itself drawn into the tussle over U.S. emissions standards if a review of current regulation leads to their relaxation.

Former U.S. Environmental Protection Agency Administrator Scott Pruitt ordered a scheduled mid-term review of the Obama-era emissions regulation to proceed, covering greenhouse-gas emissions standards for 2022-2025 model-year light-duty vehicles.

Pruitt said automakers face challenges meeting those standards, adding they raise “potential concerns related to automobile safety, and results in significant additional costs on consumers, especially low-income consumers,” according to the U.S. Federal Register. “On the whole, the Administrator believes the MY 2022 to 2025 greenhouse-gas-emissions standards are not appropriate and, therefore, should be revised as appropriate,” the notice said.

Canadian and U.S. emissions standards have been aligned since 2011, presenting a potential challenge if Washington decides to relax implementation and Ottawa doesn’t follow suit.