New White House appointees at agencies including the Federal Communications Commission, the Securities and Exchange Commission, the Interior Department and the Environmental Protection Agency have also personally intervened in recent weeks to block, delay or start the process to nullify other rules, such as a requirement that corporations publish tallies comparing chief executive pay with average employee wages.

The Trump administration has also imposed a broad regulatory freeze, instructing agencies to delay the adoption of any rules not already in effect, and to consider whether those rules should be targeted for elimination.

And it has set up barriers to enact any new regulations — such as a requirement that for each new rule, at least two others must be identified for repeal — and ordered every federal agency to create a team of employees to look for more rules that can be eliminated.

“By any empirical measure, it is a level of activity that has never been seen,” said Curtis W. Copeland, who spent decades studying federal regulatory policy on behalf of Congress while at the Congressional Research Service and the Government Accountability Office. “It is unprecedented.”