Multiple sources have confirmed that the Philadelphia Chamber of Commerce is poised to file a lawsuit seeking injunction against the city related to an equal pay law passed by Philadelphia CIty Council last year.

The bill, introduced by Councilman Bill Greenlee, bars employers from inquiring about a prospective employee's salary history, purportedly as a method of closing the gender pay gap. 

The legislation earned sharp rebukes from the chamber, major corporations with operations in the city and Republicans in Harrisburg. But the new laws also seemed to inspire additional Council bills extending further labor protections.

The exact nature of the suit is still unclear, but a staffer from Greenlee’s office acknowledged that they were aware of the impending legal action. City Hall sources say the Mayor’s Office had also been briefed on the lawsuit.

The chamber did not immediately respond to a request for comment. Sources familiar with the suit said it was expected to be filed at 10 a.m Thursday, just before council’s weekly meeting.

UPDATE: The Inquirer is reporting that Chamber CEO Rob Wonderling has said the suit will challenge the law on constitutional grounds, while sending a "signal that we would like to see a shift in the regulatory environment of our local government.”