EPA watchdog puts new scrutiny on Trump's auto emission rules

• The Trump administration's rewrite has been among the most sprawling and bitter regulatory fights in recent years, and has led to splits within the auto industry, too.
• The inspector general said the office will explore whether the rules met transparency and record-keeping requirements and "followed the EPA’s process for developing final regulatory actions."
• The new probe opens another front in the ongoing legal and political tussles over the standards.

The big picture: The prior rules would have required roughly 5% annual efficiency improvements, while the rewritten standards finalized this year mandate 1.5% year-over-year gains.

• Trump officials called the Obama standards unwieldy and said the rewritten rules will cut traffic deaths — a conclusion that critics contest.

The intrigue: The ultimate shape of U.S. auto rules will be in flux for a while. The new standards are being litigated, and if Joe Biden wins, he'd look to revive more stringent requirements and extend them.