Methanol Exposure among School Workers during Spirit Duplicator Use

Abstract

Spirit duplicators are commonly used by teachers and teaching assistants for school copying needs. Duplicating fluids often contain very high methanol concentrations. Given the lack of sufficient ventilation typically found in schools, spirit duplicator use can be a significant source of indoor air pollution. Because of the toxicity of methanol, it is of value to assess the extent of exposure among school workers. Breathing zone samples during duplicator operation were collected at five schools using a Miran 1A gas analyzer. The probability that teachers and teaching assistants would receive exposures in excess of the Occupational Safety and Health Administration (OSHA) 15-minute short-term exposure limit (STEL) of 250 ppm was calculated. Questionnaires establishing duration of duplicator use were distributed among all sampled schools. The exposure distribution among teachers was approximately lognormal, with a mean of 404 ppm and a standard deviation of 296 ppm. Exposures among teaching assistants were also approximately lognormally distributed, with a mean of 322 ppm and a standard deviation of 248 ppm. The probability that teachers and teaching assistants are receiving exposures in excess of the OSHA STEL is over 13 percent after 5 minutes of duplicator use. This probability increases to 61 percent for teachers and 46 percent for teaching assistants after 15 minutes of use. The mean maximum daily exposure duration reported in questionnaires was 18 minutes for teachers and 33 minutes for teaching assistants. It is concluded that school workers are at significant risk of exposure to high methanol concentrations during spirit duplicator operation.