The cause of worker complaints was investigated at a manufacturing facility. Workers at the electronic components manufacturing company complained of nausea, headaches, and disorientation from fumes and were taken to the hospital. The air conditioning system was checked. A diesel engine was treated for electromagnetic interference. The odor of diesel fuel filled the facility. Many employees felt they had been exposed to an unknown chemical. Environmental sampling was taken for carbon-monoxide (630080), toluene (108883), trichloroethylene (79016) (TCE) and ethyl-acetate (141786). None of these chemicals were found in concentrations exceeding recommended standards. Over the period of 1 month, several employees became ill; some exhibited a rash on face, neck, and hands. A team of industrial hygienists investigated. There were negative results in samples for TCE, formaldehyde (50000) and lead (7439921). A portable gas chromatograph was used to measure oxygen (7782447), carbon-dioxide (124389), methane (74828), and hydrogen- sulfide (7783064). NIOSH conducted a health hazard evaluation. A walk through survey was conducted, and a questionnaire was administered to 98 percent of the employees. NIOSH concluded that the episode of illness was psychogenic. Potential stresses related to production work, the repetitive nature of the work, anxiety caused by the illness outbreak and lack of knowledge about potential exposures probably caused the reported medical complaints.