Health hazard evaluation report: HETA 2002-0284-2908, Capitol Heat and Power, Madison, Wisconsin.
On June 7, 2002, the National Institute for Occupational Safety and Health (NIOSH) received a request to conduct a health hazard evaluation (HHE) at the Capitol Heat and Power (CHP) plant in Madison, Wisconsin. The requestor cited concerns regarding worker exposure to heat stress and noise during power plant operations. Health concerns listed on the HHE request included lethargy and flu-like symptoms. Two NIOSH industrial hygienists and a NIOSH medical officer visited the power plant to conduct an industrial hygiene and medical survey from July 29 through August 1, 2002. Monitoring of employee heart rates, skin temperature, and exposure to noise was conducted over two 8-hour shifts. Environmental temperatures during the same period were recorded in the facility using wet bulb globe temperature (WBGT) monitors. Workers' pre- and post-shift body weights were recorded to assess dehydration, a measure of heat strain. Private interviews were conducted with workers to gather information about health symptoms and concerns. Indoor WBGT measurements ranged from 64.9 degrees Fahrenheit (degrees F) to 88.9 degrees F, and outdoor WBGT measurements ranged from 73.8 degrees F to 93.6 degrees F. Workload categories (light, moderate, heavy, or very heavy) based on activity were assigned to each monitored employee and compared to the screening criteria in the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs). When compared to this screening criteria, results indicated that none of the five monitored workers were exposed to excessive heat stress conditions during the NIOSH survey. Heart rate monitoring data for the five consenting CHP employee participants did show that one employee had a heart rate in excess of the recommended ACGIH criterion, indicating an increased risk for heat strain. None of the six workers interviewed reported health symptoms related to heat exposure at work, nor did any experience a weight loss of greater than 1.5 percent (%) of their pre-shift weight over the course of their shift. NIOSH investigators targeted various areas within the power plant to monitor for noise. Sound levels were consistently greater than 85 A-weighted decibels [dB(A)] in the areas near the turbines and in the chiller basement near the condenser water pumps. In addition to the area noise measurements, five employees were monitored for personal noise exposure. In one instance, noise exposures exceeded the NIOSH Recommended Exposure Limit (REL) of 85 dB(A). Two employees spent most of their time exposed to noise levels between 70 and 80 dB(A), and two others spent most of their day exposed to noise levels between 70 and 90 dB(A). In response to employee concerns, air samples for bromine were taken at the pellet storage tank and near the cooling tower. Colorimetric readings from the bromine detector tube did not indicate a presence of bromine at detectable levels. NIOSH investigators observed that communication between CHP management and employees was a problem at the time of this survey. There appeared to be a lack of regular, ongoing communication and training regarding health and safety issues within the plant. NIOSH investigators concluded that there is a potential for heat stress conditions to exist in the plant; one monitored worker showed signs of heat strain on the day of the survey. A plan to increase awareness of heat exposure should be implemented. Noise levels recorded in the plant indicate that a hearing conservation program is necessary for all employees. Communication between employees and management needs to be improved, especially in the areas of health and safety training and responsibilities.