Abstract: At approximately 4:00 a.m. on December 1, 1992, employees of Sweetwater Distributors started their workday in a refrigerated warehouse. Propane powered forklifts were used. The employer had recently upgraded the insulation and sealing. By late morning, Employee #1 was experiencing flu-like symptoms and was sent to a primary care clinic, where blood gas testing was ordered. His carboxyhemoglobin tested at 41.5 percent. Employees #2, #3, and #4 were tested that afternoon. Their carboxyhemoglobin test results are unknown. The warehouse air space was sampled with direct reading Murigard III and Drager tubes, recording values as high as 77 ppm with the direct reading instrument and 125 ppm with Drager 2/3 tubes. The employer was directed to ventilate the warehouse and office space overnight. The following morning, no significant readings were obtained (3 to 6 ppm). On December 1, 1992, at noon, the employer had obtained two electric forklifts and had sidelined the propane powered lifts, which will no longer be used in the refrigerated space.