A group of Senate Democrats says the Occupational Safety and Health Administration has done so little to protect workers during the coronavirus pandemic that they want an audit of the agencys enforcement efforts since March.

In a letter Wednesday, the lawmakers asked the Labor Departments inspector general to investigate OSHAs inspections and citations ever since workers began getting sick with COVID-19. They also asked the watchdog to probe the agencys decision not to implement an emergency standard to deal with the virus.

Citing a drop in workplace investigations, the senators wrote that they have grave concerns that OSHA is failing to meet its core mission of protecting worker health and safety during the COVID-19 pandemic.

The letter was spearheaded by Sen. Elizabeth Warren (Mass.) and cosigned by fellow Democrats Tim Kaine (Va.), Tammy Baldwin (Wis.), Bob Casey (Penn.) and Tammy Duckworth (Ill.), as well as independent Sen. Bernie Sanders (Vt.).

In a statement to HuffPost, Warren said OSHA has let employers off the hook and refused to take even the most basic steps to protect workers during this crisis.

A Labor Department spokesperson disputed the lawmakers characterization of OSHA enforcement.

With respect, the Senators letter paints a grossly inaccurate picture of the unprecedented response by OSHA and the federal government as a whole to the coronavirus pandemic, the spokesperson said in an email. The Department is committed to protecting American workers during the pandemic, and OSHA has been working around the clock to that end.

Democrats and workplace safety advocates have been hammering OSHA , which is part of the Labor Department, for going easy on employers during the pandemic. The agency has issued a raft of new guidance in recent weeks, but it is merely advice for employers on how to keep workers safe not legally enforceable measures that come with citations.

Former OSHA officials from the Obama presidency have harshly criticized the agencys leadership under Trump for not issuing an emergency standard that would require certain employers to follow clear protocols for the coronavirus.

Critics also say the agency should be using every tool it has from fines to the bully pulpit to pressure employers to follow social distancing measures and provide protective equipment for workers.