Sen. Elizabeth Warren (D-Mass.) is looking for answers from the Labor Department’s top attorney on how the DOL’s lawyers are handling wage, hour, and other enforcement cases involving workers with arbitration agreements.

Warren, a White House hopeful and member of the Senate Health, Education, Labor and Pensions Committee, in a March 27 letter asked Labor Solicitor Kate O’Scannlain to explain recent comments on the issue. O’Scannlain told a group of lawyers in New York last month that the department hasn’t taken a definitive stance on whether it will pursue lawsuits against companies in cases where the workers have signed arbitration agreements.

“Your comments were troublesome to the extent that they implied anything less than a firm commitment to pursue enforcement actions and/or litigation against employers using forced arbitration agreements when they have broken the law,” Warren said in the letter. “DOL’s failure to act in these cases would amount to a disturbing change in policy that would strip important protections from millions of workers who need them most.”

Major tech companies have recently faced criticism for requiring employees to agree in advance to arbitrate claims stemming from sexual harassment or assault and other workplace claims. These agreements often come with a confidentiality requirement, which critics have blamed for helping shield serial abusers. They also often ban workers from bringing claims collectively, which can create a barrier for low-wage workers.

Arbitration agreements between a company and its workers aren’t legally binding on the DOL. The department still has the power to enforce a large group of workers’ wage-and-hour and other rights in open court if department lawyers choose to exercise that authority.

The DOL declined to comment for this story.

O’Scannlain has asked lawyers in regional offices to flag cases involving arbitration agreements. She was asked at a Practicing Law Institute event in New York City in February about what the department will do in those cases.

“We continue to have the authority to bring our enforcement matters even if an arbitration agreement exists,” she said. “But it’s something I care about knowing because we do have limited enforcement resources and I want to make sure we are using our limited resources in the most efficient and effective way. If there are other avenues for people to pursue, I want to know that.”

Warren’s letter cites Bloomberg Law’s reporting on O’Scannlain’s comments.

“Given the importance of DOL’s responsibility to enforce our nation’s most basic labor laws in cases where employees were required to sign forced arbitration agreements, I am deeply concerned that the Department may be considering dismantling this backstop,” Warren’s letter goes on to say.