President Joe Biden wants unvaccinated workers to pay for office Covid-19 testing. But their employers could still end up footing much of the bill. The administration says firms can make employees who opt out of the shots pay for required weekly testing. Business groups and labor-law experts argue that existing laws will likely require companies to cover those costs for workers who claim religious or disability exemptions to the Covid-19 vaccines, at a price that could reach hundreds of dollars per person each month. The prospect of hitting businesses with new testing costs as many struggle to staff back up could harden opposition to Biden’s plan, and hamper the president’s latest push to end the pandemic. It also comes at a politically dicey moment for Biden and Democrats, who faced surprise losses in the early November elections and have struggled to push their infrastructure and social safety-net legislation through Congress. Already, several Republican governors have filed suits challenging the employer vaccine mandate, as have the Republican National Committee, the small-business group Job Creators Network and several individual firms. A Department of Labor spokesperson said that “payment for the costs associated with testing pursuant to other laws or regulations not associated with the OSH Act is beyond OSHA’s authority and jurisdiction,” in response to questions about employers’ concerns. But the spokesperson also noted that some companies might choose to pay for testing, in part or in full, “as an inducement to keep employees in a tight labor market.” Others may try to make affected employees pay for the screening, the spokesperson added.