Led by the Service Employees International Union, National Nurses United and the AFL-CIO, dozens of labor unions last week issued a letter urging Congress to resist Republican efforts to use the Congressional Review Act to overturn some workforce rules enacted by the Department of Labor and other US agencies.

“Plainly, the CRA has become the latest weapon in a war on workers waged by special interests,” the organizations said, citing resolutions, “some of which already passed the Congress, [that] carry a threat of permanently undermining critical gains for working people across the country.”

Since the CRA became law in 1996, the unions said, it has only been invoked 20 times, with 16 of those efforts occurring during the first two years of former President Donald Trump’s time in office.

Among efforts to use the CRA to overturn labor protections, according to the letter, the GOP has sought to negate improvements to wage and hour law enforcement under the definition of independent contractor, protections for workers’ retirement savings and ensuring workers’ right to designate a representative to accompany the OSHA inspector on a walk-through of a job site and expanding workers’ right to overtime pay.

“We ask that you not allow private equity, the financial industry, multinational franchisors,

union-busters, or other special interests to use this tool to undo the progress that workers are making via federal rulemaking,” the unions said.