In April 2000, the National Institute for Occupational Safety and Health (NIOSH) received a request for a Health Hazard Evaluation (HHE) from employees at Winnebago Industries, Inc. in Forest City, Iowa. The HHE request expressed concerns regarding exposures to airborne wood dust during woodworking operations in the production of interior components of motor homes. In response to this request, a site visit was conducted September 12 - 14, 2000. During this site visit, two NIOSH industrial hygienists and a NIOSH occupational physician conducted a walk-through survey of the sawmill building and discussed the issues with management and employees in the area. Full-shift, personal breathing zone (PBZ) air sampling was performed to measure the levels of exposure to wood dust generated during the normal operation of the facility's woodworking machines such as sanders, routers, saws, and planers. Discussions were held with management regarding the ventilation system plans, personal protective equipment program (PPE), and environmental monitoring programs. Personal interviews were held with employees regarding their medical history and present health concerns related to the potential wood dust exposures. The Occupational Safety and Health Administration (OSHA) has no specific permissible exposure limit (PEL) for wood dust and therefore regulates it as Particulates Not Otherwise Regulated (PNOR). The results for seventeen air samples showed that no exposures were above this limit of 15 milligrams/cubic meter (mg/m3) as an 8-hour time-weighted average (TWA). However, seven individuals' exposures were above the NIOSH recommended exposure limit (REL) for wood dust of 1 mg/m3 as a full-shift TWA. These exposures included one hand router in each of Departments 804 and 806. These results were 2.2 mg/m3 and 1.9 mg/m3, respectively. The other area in which results showed exposures over the REL was Department 811. The activities performed during these over-exposures were disc hand sanding (1.1 mg/m3 and 1.3 mg/m3), 'Time-Saver' pre-sanding (1.8 mg/m3), trimming (2.6 mg/m3), and the use of a swing saw (1.3 mg/m3). Interviews with employees showed that workers from Department 811 reported experiencing possible work-related respiratory health effects that were not reported by the general area employees. The most commonly reported symptoms included respiratory irritation, nasal congestion, cough, and shortness of breath

less commonly reported were dry nasal and throat mucous membranes, bloody nasal mucous, sore throat, burning of the eyes, and generalized fatigue. Employees in Department 811 were also more likely to report perceived elevated dust levels in the work area than employees in other departments. NIOSH investigators concluded that a potential health hazard exists at this Winnebago Industries Inc. facility. Results from PBZ sampling showed that a number of individuals working in Department 811 were exposed to wood dust concentrations above the NIOSH REL. Additionally, two individuals working with hand routers in ventilation booths were also exposed to levels of airborne wood dust above the REL. The data collected from our survey suggests that employee symptoms were consistent with the known effects of wood dust exposure and that respiratory health effects appear to be more commonly experienced by workers in Department 811. Recommendations are made in this report concerning further evaluation and control of exposures to wood dust in these areas.