Workers who "blow the whistle" on prohibited practices play a role in enforcing federal laws, but these workers risk reprisals from their employers. The Whistleblower Protection Program at the Department of Labor's (Labor) Occupational Safety and Health Administration (OSHA) is responsible for investigating whistleblowers' complaints. OSHA's decisions generally may be appealed to the Office of Administrative Law Judges (OALJ) and, ultimately, the Administrative Review Board (ARB). GAO examined (1) what is known about processing times for complaints and what affects these times, (2) what outcomes resulted, and (3) what challenges OSHA faces in administering the program. To answer these questions, GAO analyzed electronic data files from OSHA, OALJ, and ARB; visited five OSHA regional offices; reviewed case files; conducted a Web-based survey of investigators; and interviewed key officials.