Four U.S Senators have sent a letter to Lina Khan, the chairwoman of the Federal Trade Commission (FTC), expressing concerns that Activision Blizzard’s pending acquisition by Microsoft has “impeded unionization efforts and undermined workers’ calls for accountability.” The letter, sent by Sens. Elizabeth Warren, Bernie Sanders, Sheldon Whitehouse, and Cory Booker, asks the FTC to oppose the acquisition if it is found to “enhance monopsony power and worsen the negotiating position between workers and the parties to this deal.”

Prior to and throughout the process of being acquired by Microsoft for a total of $68.7 billion, which far outpaces any previous acquisition in the game industry, Activision Blizzard has found itself under the scrutiny of multiple government organizations. The company recently settled a lawsuit brought forth by the Equal Employment Opportunity Commission regarding claims of sexual harassment and gender-based discrimination in the workplace taht created an $18 million fund for claimants.

The California Department of Fair Employment and Housing, which first brought allegations of misconduct and discrimination at Activision Blizzard to light, is continuing its case against the company. This case, along with the financial woes it brought to Activision Blizzard, eventually led to Microsoft’s acquisition of the company.

Likewise, Activision has seen a surge in unionization efforts since Microsoft’s announcement that it intends to purchase the gaming giant. In January, 34 QA staffers at Activision’s Raven Software, the developer for the publisher’s hit battle royale title Call of Duty: Warzone, voted to form a union. Activision has since refused to voluntarily recognize that union and reorganized Raven Software’s QA department, spreading many of its members across multiple departments rather than keeping them in one cohesive unit.