The Health Hazard Evaluation Program received a request from management of a warehouse and distribution facility concerned about the potential for work-related coccidioidomycosis, also known as Valley fever or "cocci." Several employees developed coccidioidomycosis in recent years. The warehouse and distribution facility consisted of multiple buildings on several hundred acres mostly surrounded by farmland. We interviewed employees about work characteristics, time spent outdoors at and outside of work, residence in areas where Coccidioides has been found, and personal health

observed work practices and conditions

assessed the ventilation systems

reviewed policies and procedures

and identified cases of coccidioidomycosis among employees. We found that employees could possibly breathe in dust during indoor and outdoor work. We identified at least 10 cases of coccidioidomycosis among facilities during January 2014-April 2019. However, it was not possible to determine whether this represented an excess risk of coccidioidomycosis at this workplace or whether exposure to Coccidioides occurred at work or outside of work. Most employees reported performing job activities outdoors or handling materials that were dusty from being outdoors. Housekeeping practices varied in the buildings we visited. Some areas used dry sweeping, which can generate dust. While the facility's respiratory protection plan outlined that an exposure assessment was to be performed to determine required or voluntary respirator use, an exposure assessment for airborne dust was not documented in the respiratory protection plan we reviewed. Although management reported that respirator use for dust was voluntary, communications to employees were unclear on whether respirator use was voluntary or required during excessive wind conditions. We recommended reducing airborne dust exposure by keeping warehouse bays, doors, and windows closed

using a wet sweeping method or a filtered vacuum to capture dust

choosing machinery with closed cabs and increased filtration when replacing equipment

and cleaning and maintaining window air-conditioning units in warehouse breakrooms. We also recommended conducting exposure assessment(s) to determine whether respirator use to prevent dust exposure should be required or voluntary, instructing employees voluntarily wearing N95 filtering facepiece respirators on how to wear them properly, and improving communication with employees about Coccidioides exposure and coccidioidomycosis.