Abstract: Employee #1 and a coworker were assigned to replace the dampener cylinder of a galvanizing furnace. After four short trips of 5 to 15 minutes, for a total of approximately 40 minutes, it was noted that Employee #1 was experiencing symptoms of carbon monoxide poisoning, including blurred vision, discharge, dry heaves, drowsiness, staggering, and slurred speech. Employees were using a direct reading carbon monoxide meter and observed carbon monoxide levels of 200 to 500 ppm. The meter had been placed on a work surface during the repair operations and its sound and light alarms were not noticed. The alarm was also below ambient sound levels and the meter was not capable of determining 8-hour exposures. Employees had been instructed to return to the area after activation of the meter's 180 ppm level alarm. Employees were not fully advised of the hazards of carbon monoxide or of the company's written policy covering carbon monoxide detection procedures.