Health Hazard Evaluation Report: HETA-2011-0047-3143, October 2011. Multiple Sclerosis Cluster Evaluation in an Inpatient Oncology Ward - Wisconsin

摘要

In January 2011 NIOSH received an employee HHE request concerning a potential cluster of MS cases among nurses employed in the inpatient oncology unit of a university hospital in Wisconsin. The request detailed concern about acrolein as a potential exposure from metabolized chemotherapy drugs used in the unit (cyclophosphamide and ifosfamide) and as a component of helicopter exhaust from the nearby hospital landing pad. We visited the hospital on May 23-24, 2011. We observed work processes, practices, and conditions in the oncology unit. We interviewed employees in the unit about their concerns related to chemotherapy drugs. We collected surface wipe samples for two chemotherapy drugs used in the unit, cyclophosphamide and ifosfamide. Additionally, we examined the helicopter landing pad and its proximity to the outdoor air intake for the ventilation system for the oncology unit and sampled for CO (a constituent of the helicopter exhaust). We interviewed all 29 employees working first or second shift in the unit, and one employee by phone. Of the interviewed employees, 17 reported no work-related symptoms. The remaining employees reported symptoms, including headache, dizziness, nausea, and light sensitivity, when they smelled helicopter exhaust. None of the unusual patterns of reproductive health problems that can occur with exposure to many chemotherapeutics were seen. The three employees with MS were all women within the average age range for diagnosis of MS; none had a family history of MS. On the basis of what we currently know about the epidemiology, characteristics, and treatment of MS, it is unlikely that these cases are associated with workplace exposures, including acrolein. Most of the surface wipe samples we collected for cyclophosphamide and ifosfamide were below the LOQ; only one sample was above the LOQ. CO concentrations were well below OELs. We found that under certain meteorological conditions helicopter exhaust could enter the ventilation system of the unit. We recommended that the unit continue to control exposures to chemotherapy drugs to levels as low as are reasonably achievable because some of these drugs are considered hazardous (NIOSH 2010a). Control of exposures can be validated by routine surface sampling for chemotherapy drugs used in the unit.