Abstract: At approximately 7:00 p.m. on June 12, 2007, Employees #1 and #2, construction carpenters, became ill with symptoms of nausea, metallic taste, and bluing of the lips. The two employees were building a wooden box to be used as a form to pour concrete around at a coal fired power generation plant, where contractors were in the beginning stages of building a nitrous oxide scrubber system. The incident occurred in an open area and no hazardous chemicals were in use. Air sampling was conducted immediately after the incident by the company and continued until the compliance inspection started. The day after the first incident occurred, a second employee suffered from similar symptoms even though he was not doing the same activity. The company did continuous air sampling for several days and did not obtain any high readings. Additional sampling was also conducted on employee drinking water and soil samples with no significant findings. Employees #1 and #2 were not hospitalized for treatment.