Abstract: On January 4, 1994, workers began to experience symptoms of headaches and dizziness. At approximately 9:00 a.m. on January 6, 1994, Employee #1 and coworkers were evacuated from the building complaining of headaches, dizziness, and nausea; Employee #1 was admitted to the hospital. Carboxyhemoglobin tests revealed a level of 22.3 percent in her blood. Outside contractors from the gas company were brought in to test the air and evaluate problems, but nothing was found. The inspector sampled for carbon monoxide on January 6 and January 10, 1994; levels were below 3 ppm. A possible gas leak over the weekend of January 1-3, 1994 was considered. HVAC had been shut down then but not removed from the building.