This report describes a patient who developed acute chemical pneumonitis following overexposure to metal mercury vapor. The exposure occurred in a gold extraction facility where a gold-mercury amalgam was heated in a confined area. Prompt treatment with penicillamine and corticosteroids was instituted; radiologic pulmonary infiltrates disappeared within a week, but there was little change in the pulmonary function abnormalities (restriction and diffusion impairment) over the period of 11 months of follow-up. This raises the possibility of persistent pulmonary function impairment after metal mercury vapor-induced chemical pneumonitis.