Abstract: On September 5, 1995, a report was filed by the Patton State Hospital's safety officer regarding Employee #1's possible exposure to mycoplasma pneumonia. Employee #1 had not been hospitalized. On October 3, 1995, a second report was filed by the employer regarding an exposure to Employee #2 that occurred on August 28, 1995. Employee #2 had been hospitalized for more than 24 hours. Prior to September 1995, Patton State Hospital had been aware of a developing respiratory illness thought to be caused by M. pneumonia. CAL/OSHA, CDC, DHS, and other agencies were contacted to assist the employer and to review and recommend control measures for the apparent outbreak. Patton State Hospital employs approximately 1,500 workers and the hospital's primary mission is to treat mentally disordered offenders. Factors causing the outbreak were not determined due to the nature of the infection and because it occurs endemically within the community.