Revision of the NLRB’s joint-employment rule was opposed by attorneys general from 10 states and District of Columbia. The group sent a letter to the board on Friday; the same day, the board extended the public comment period on proposed its changes to the rule.

“The National Labor Relations Board is entrusted with protecting workers, not putting them in harm’s way,” New York Attorney General Letitia James said. “These proposed rules would limit legal protections for workers, compromise collective bargaining and allow companies to potentially evade justice for labor violations.”

James is leading the effort along with Pennsylvania Attorney General Josh Shapiro.

The National Labor Relations Board hopes to put in a place a rule to reverse a 2015 decision by an earlier board that had expanded the definition of joint employment between staffing firms and client companies.

Its 2015 decision made client companies joint employers even if they exercised only indirect control over workers. The 2015 case found that Browning-Ferris Industries of California was a joint employer with staffing firm Leadpoint Business Services at BFI’s Milpitas, Calif. recycling site. The decision came after a union effort to organize workers at the location.

The board had already begun collecting comments on its proposed new rule. However, the US Court of Appeals for the DC District ruled on Dec. 28 that a company could be a joint employer even if it has only indirect control or reserved control. Still, it sent the case back to the NLRB to resolve other questions.

As a result, the NLRB extended its comment period Jan. 28 in light of the court decision. Comments replying to other comments must be received by Feb. 11.

Attorneys general noted that reversing the 2015 decision could resulting in loss of bargaining power for workers and result in lower wages and fewer protections.

“As our economy and labor markets continue to evolve, our laws should keep pace to strengthen protections for workers, not weaken them,” said California Attorney General Becerra, one of those taking part in the letter. “The NLRB’s proposal reverses course and leaves contracted workers without recourse to effectively bargain with companies that have broad control over their working conditions.”

Taking part in the letter attorneys general from California, New York, Pennsylvania, Illinois, Maryland, Massachusetts, New Jersey, Oregon, Virginia, Washington and the District of Columbia.