[On-site epidemiological investigation of a carbon monoxide poisoning incident]

Nighteen people at a restaurant experienced dizziness headaches and other discomforts in six days. According to the description method, the time and location distribution were found to be concentrated. A second Investigation was conducted at the same time as the onset of the case, the test found that the carbon monoxide concentration of second floor up to 539 mg/m(3). The on-site testing found that when 2 steam generator in snack room on the first floor turned on, the carbon monoxide concentration on the top of elevator on the second floor was 1225.0 mg/m(3). After the accident, the restaurant replaced a steam generator, the carbon monoxide concentration on the top of the new and old steam generator were 350 mg/m(3) and >1 000 mg/m(3), respectively. After the steam generators were fitted with exhaust smoke pipe and exhasust hood, the carbon monoxide concentrations of on the top of the vegetable transfer elevator and the room on the second floor were both 0.4 mg/m(3), and there were no cases of recurrence. It was determined that this was a carbon monoxide poisoning incident caused by a high concentration of carbon monoxide emitted by the steam generators, which spread to the second floor of the private room through the vegetable transfer elevator.