After making headlines for secretly overcharging Metro customers for years, the transit agency is under fire again from one of its biggest unions, which accuses General Manager Paul Wiedefeld of threatening the public's health and safety. WMATA has been outsourcing custodial work usually done by members of ATU 689, in what the union calls a “blatant” violation of its contract. The resulting “unreliable custodial work” poses potential security risks, Local 689 said Wednesday, pledging to take collective action unless Wiedefeld complies with the contract by this Sunday.