Flex, the trade association representing app-based rideshare and delivery platforms in the US, sent a letter to President Biden calling for a delay in further action on the Department of Labor’s proposed worker classification rule until the US Senate confirms a new labor secretary.

The letter, dated March 20, also requests that the president’s current nominee to lead the DOL, Julie Su, explain in detail — up to and through the Senate committee confirmation process — how she intends to implement the proposed regulation.

The DOL in October proposed a rule that would make it more difficult for companies to treat workers as independent contractors, which would shake up ride hailing, delivery and other industries that rely on gig workers. A final rule was subsequently slated for May.

Reuters reported that Democrats’ narrow control of the Senate means Su’s confirmation is unlikely to be impacted, but the final worker classification rule is expected this year, and the push to lobby against it by groups such as the Flex Association is picking up momentum.

Flex — whose member companies include DoorDash, Grubhub, HopSkipDrive, Instacart, Lyft, Shipt and Uber — also expressed its concern that Su “does not fully appreciate” the potential impact of policies that undermine independent work on both workers and their customers and has a record indicating an “oppositional approach” to policymaking.

“As California’s Secretary of Labor, Ms. Su was significantly involved in the state’s AB 5 legislation, which wreaked havoc across multiple industries,” the letter states. “If the law had not been eventually amended by ~60% of California voters in a ballot measure, the statute could have undercut more than a million people who choose flexible work. Ms. Su should explain to the American people how she plans to avoid similar policies as head of the DOL, which could lead to upheaval that is national in scope.”

The letter, available online and signed by Flex CEO Kristin Sharp, asks that Su throughout the Senate Committee process “clearly articulates and distinguishes her previous California policy priorities from her potential priorities for the US DOL, as those she pursued during her tenure as California Secretary of Labor, if enacted at the federal level, would harm this diverse group of independent entrepreneurs and so that stakeholders can properly evaluate their position on her nomination.”