The Communications Workers of America as well as several individuals filed a federal lawsuit Wednesday alleging that Amazon.com Inc. AMZN, +0.30% , T-Mobile US Inc TMUS, +1.82% . and several subsidiaries of Cox Enterprises Inc. sought to discriminate by age in several job ads on Facebook Inc. FB, -0.10% . The suit alleges that the defendants used Facebook ad-targeting tech to "routinely exclude older workers from receiving their employment and recruiting ads on Facebook, and thus deny older workers job opportunities." The story was first reported by the New York Times and ProPublica. Plaintiffs included several examples of the ads in court papers, including one from Facebook itself, that allegedly used Facebook's targeting technology to make job ads invisible from older Facebook users. Federal statutes such as the Age Discrimination in Employment Act, which prohibits discrimination of people over 40, and laws in some states, prohibit bias against hiring workers of certain ages. Facebook defended its targeting. "Used responsibly, age-based targeting for employment purposes is an accepted industry practice and for good reason: it helps employers recruit and people of all ages find work," Facebook vice president Rob Goldman said in a statement to the Times.