House Republican leaders, including chairmen of all committees, have sent a letter to all departments and agencies warning them against so-called “midnight” rule-making at the end of an administration.

“As you are aware, such action often involves the exercise of substantial policymaking discretion and could have far-reaching impacts on the American people and economy,” it says. “Considering these potential consequences, we write to caution you against finalizing pending rules or regulations in the administration’s last days.

“By refraining from acting with undue haste, you will ensure that agency staff may fully assess the costs and benefits of rules, making it less likely that unintended consequences will harm consumers and businesses. Moreover, such forbearance is necessary to afford the recently elected administration and Congress the opportunity to review and give direction concerning pending rulemakings,” it adds.

The letter warns that agencies that “ignore this counsel” will have their actions scrutinized and possibly overturned under the Congressional Review Act, which allows Congress to override rules finalized after May 30 of this year with a simple majority vote, rather than the higher threshold generally needed in Senate voting.

It’s been estimated that some 100 major rule-making initiatives remain pending, including on major issues such as the environment and health care.