Carbon monoxide in school buses

Following an incident in which eight children became ill from carbon monoxide in a school bus, an investigation was made of CO levels in school buses in the Seattle area. The procedure selected for the evaluation was to test a large number of buses at a nearby ski resort. On the day selected for the sampling over 200 buses arrived, bringing school children from a number of school districts in the Seattle area for skiing lessons. As they arrived, 33 buses were checked immediately to determine in transit levels of CO. Four of the 33 buses had CO levels in excess of Environmental Protection Agency maximum allowable concentrations for an 8 hr exposure. As the buses sat idling in the parking lot, 65 of them were tested, during the lunch hour when the students returned to the buses to have their lunch and to rest. Two buses had nearly 3 times the concentration of CO permitted by the EPA for a 1 hr exposure. A total of seven buses (10 per cent) had concentrations of CO not permitted by the EPA for more than a 1 hr period. Altogether there were 24 buses (36 per cent) that had levels of CO in excess of EPA standards for an 8 hr exposure. As a result of these determinations and other observations a number of recommendations were made to reduce the hazard of exposure to carbon monoxide in school buses.