The medical surveillance requirements of the Occupational Safety and Health Administration's (OSHA) ethylene oxide (EtO) standard became effective in 1985. However, little is known about the nature of the response of EtO users to this regulatory requirement. In an effort to begin to understand this, we conducted a survey of EtO health and safety in Massachusetts hospitals (n = 92). We determined the cumulative incidence of provision of EtO medical surveillance, the characteristics of the surveillance interventions provided, and the clinical findings of EtO medical surveillance efforts in Massachusetts hospitals. From 1985 to 1993, medical surveillance for EtO exposure was provided one or more times in 62% of EtO-using hospitals. Sixty-five percent of EtO medical surveillance providers reported performance of all five medical surveillance procedures required by OSHA's EtO standard. Medical surveillance provider certification in occupational medicine or nursing, and a greater extent of coverage of written medical surveillance policies, were related to higher likelihoods of fulfillment of OSHA-required procedures. Twenty-seven percent of medical surveillance providers reported detection of EtO-related symptoms or conditions, ranging from mucous membrane irritation to peripheral neuropathy. These findings reveal wide-spread implementation of OSHA-mandated EtO medical surveillance, with concomitant incomplete fulfillment of OSHA-specified procedures. From the provider-based survey, we estimate that one or more workers at 19% of EtO-using Massachusetts hospitals have experienced EtO-related health effects.