Occupational exposures during routine activities in coal-fueled power plants

Limited information is available on occupational exposures during routine, nonoutage work activities in coal-fueled power plants. This study evaluated occupational exposures to the principal contaminants in the facilities, including respirable dust (coal dust), arsenic, noise, asbestos, and heat stress. The data were collected over a 3-month period, during the summer of 2001, in 5 facilities that were chosen to be representative of the coal-fueled power plants of a large southeastern power-generating company. Each of the facilities was divided into 5 similar exposure groups based on previous exposure assessments and job tasks performed. From 4 of the 5 facilities, 392 air samples and 302 noise samples were collected with approximately 50 respirable coal dust, 32 arsenic, 15 asbestos, and 70 noise samples from each of the 4 plants. One of the previously surveyed facilities was also evaluated for heat stress, and 1 additional coal-fueled power plant was surveyed for a total of 20 personal heat stress samples. Personal monitors and area WBGT monitors were used. Of the nearly 400 air samples collected, only 1 exceeded the allowable occupational exposure value. For the noise samples, 55 (approximately 18%) were equal to or greater than the Occupational Safety and Health Administration (OSHA) 8-hour hearing conservation program level of 85 dBA, and 12 (approximately 4%) were equal to or greater than the OSHA 8-hour permissible exposure level of 90 dBA. Heat stress monitoring at the facilities indicates that 26% of the 1-hour TWAs were exceeded for one or all of the recommended heat stress limits. The data also concluded that some work sites were above the heat stress ceiling values recommended by the National Institute for Occupational Safety and Health (NIOSH). Four of the 20 employees personally monitored exceeded the recommended limits for heart rate or body core temperature. This suggests there is a potential for heat strain if signs and symptoms are ignored. Recommendations are made to better control the heat stress exposure.