On November 13, 2002, the National Institute for Occupational Safety and Health (NIOSH) received a confidential employee request to conduct a health hazard evaluation (HHE) at Degesch America, Inc., Weyers Cave, Virginia. The request identified several health concerns believed to be due to exposure to Phostoxin and Magtoxin fumigants manufactured at Degesch America. The HHE request listed the following health problems occurring in workers following occupational exposure: cyanosis, chest pain, nausea, weakness, dizziness, difficult breathing, low blood pressure, seizures, disorientation, muscle twitch, tremors, cough, indigestion, gastric problems, numbness, and cardiac problems. On February 20, 2003, NIOSH investigators conducted a site visit at Degesch America. The purpose of the site visit was to review the manufacturing process, collect air samples, review pertinent safety and health records, and conduct worker medical interviews to determine if the reported symptoms are related to workplace exposure. An opening conference was held with employee and management representatives. Following this meeting, a walk-through survey of the plant's blending, tableting, packaging, and warehouse areas was conducted. Following the walk-through, NIOSH investigators collected general area (GA) and personal breathing zone (PBZ) air samples for phosphine, ammonia, elements, total dust, and volatile organic compounds (VOCs). The NIOSH medical officer interviewed employees. None of the air samples collected by NIOSH for ammonia, VOCs, elements, or particulates yielded concentrations in excess of any published occupational exposure limits. However, phosphine exposures during cleaning of the tablet hood were equal to the NIOSH STEL. Four of ten interviewed employees reported isolated instances of health effects that they believed to be consistent with past occupational exposures to Phostoxin, Magtoxin, or aluminum phosphide. Overall, the occurrence of symptoms attributable to occupational exposures at Degesch America has been rare. Nonetheless, occasions for exposure to phosphine levels in excess of exposure limits may occur. Even though engineering controls have been adequately implemented, additional focus can be placed on the respiratory protection program, air monitoring of the transferring of cured pellets, phopshine monitor sensor location in the blend and tablet areas, and inspection of hoppers for leaks. Recommendations in the report address these issues.