A group of major U.S. companies that use Facebook's platforms to advertise job opportunities violated state and federal employment law by discriminating against older applicants, according to a newly amended complaint filed Tuesday in San Francisco federal district court.

The complaint, which now includes federal claims under the Age Discrimination in Employment Act and additional California state claims, alleges hundreds of companies that use Facebook to advertise job postings discriminate against older workers by targeting ads exclusively to a younger demographic. The original complaint was filed in December.

The litigation is unfolding as Facebook's advertising platform comes under increased scrutiny on a variety of fronts. U.S. lawmakers and the AARP have criticized the social media giant's advertising practices. The law firm Outten & Golden, which brought the California suit, has filed dozens of age-bias allegations with the U.S. Equal Employment Opportunity Commission against Facebook and other companies.

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The plaintiffs, including the Communications Workers of America, said the EEOC on May 10 issued a right-to-sue letter regarding claims under the Age Discrimination in Employment Act. Separately, the plaintiffs said they received a right-to-sue letter on May 22 from the California Department of Fair Employment and Housing.

The lawsuit identifies by name dozens of employers—including T-Mobile, Amazon.com, Cox Communications and Capital One—that use Facebook to send job and employment-related ads allegedly hidden from older workers. Defendants have denied that their recruitment efforts are discriminatory.

An Amazon spokesperson said in a statement: “Amazon is an equal opportunity employer. We follow all state and federal employment laws, but we have a longstanding practice of not commenting on pending litigation. Our approach is and always has been to seek all qualified candidates over the age of 18.”

The amended complaint also targets Facebook's algorithm itself, alleging that it uses age to decide which users will receive job advertisements. Facebook is not a named defendant in the California case.

“Facebook itself decides within a population selected by an employer or employment agency to receive a job advertisement which Facebook users will actually receive the advertisement, and in making this decision about which users will receive the job ads Facebook considers the age of its users; and often, this means that a disproportionate number of job ads are sent to younger workers instead of older workers,” the complaint said.

Outten & Golden's Peter Romer-Friedman in Washington said the plaintiffs “plan to use every tool in our toolbox to stop the practice and make sure that they treat everyone fairly moving forward. The allegation that the algorithm discriminates against older workers is an extremely important one.”

A Facebook spokesperson was not reached for comment about the amended complaint.

The lawsuit asks the court, among other things, to declare that the advertising and recruitment practices violated the Age Discrimination in Employment Act, and the suit seeks an injunction that stops companies “from continuing to engage in acts that violate the same federal and state statutes.”

A U.S. Senate committee has launched an investigation into age discrimination practices highlighted in the lawsuit. Romer-Friedman said addressing this issue could represent the wave of the future in discrimination cases.

“The takeaway here is that algorithms may not care about civil rights laws, but we do and the law does,” Romer-Friedman said. “We plan to hold Facebook accountable regardless of how or why it discriminates. This is a sign that we are stepping up our efforts to enforce the law.”

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