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In-depth survey report: styrene and noise exposures during fiber reinforced plastic boat manufacturing at Larson/Glastron Inc., Little Falls, Minnesota.

Valladares RM; Gressel M; Feng HA; Kardous C; Blade LM; Hammond D; Farwick D
Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, EPHB 306-11a, 2005 Jul; :1-33
A survey was performed to assess the occupational exposures to styrene and noise, and to evaluate the effectiveness of engineering controls for styrene in two distinct fiberglass reinforced plastic (FRP) boat manufacturing plants. The primary objective of this study was to quantify the exposures occurring in both an open and closed mold plant and to evaluate the installed engineering controls to reduce styrene exposure. The effectiveness of the styrene controls examined in this study was evaluated by measuring styrene personal breathing-zone and general-area samples during typical work shifts. The ventilation system in Plant 7, the closed mold plant, appeared to be relatively effective for controlling the amount of styrene-area vapors released into the air. Results showed this closed mold system controlled styrene vapor concentrations in the air from 0.14 parts per million (ppm) in areas upwind of the styrene emitting source, to 3.7-12.2 ppm inside the actual Virtual Engineered Composites (VEC) cells. Personal breathing-zone exposures for employees working in the molding areas ranged from non-detected to 20.7 ppm. While these full shift samples were not above the NIOSH Recommended Exposure Level (REL), a comparison between the laminators who spray gelcoat and the loaders who do not, suggests short-term exposures during gelcoat spraying may be a concern. Area samples taken in the resin and gel coat storage rooms showed concentrations, ranging from non-detected to 39.0 ppm. Results for the open mold plant (Plant 6) were markedly different, indicating the installed control systems were not as effective in controlling styrene exposures. The personal breathing-zone exposures, in Plant 6, ranged from 22.8 to 103 ppm with geometric mean exposures ranging from 30.3 ppm (gelcoater) to 82.8 ppm (hull roller). The general-area concentrations measured ranged from 2.2 ppm in the northeast region to 28.7 ppm in the southwest region. Upgrades to the local exhaust ventilation system in Plant 6 should be a priority. The current ventilation system is not working to its maximum potential and thus allowing workers to be exposed to concentrations of styrene vapors above the NIOSH REL and near the OSHA PEL. In Plant 7, the source(s) of the fugitive styrene emissions in the resin and gel coat storage rooms should be identified and controlled. The exposures measured in the gelcoat room are assumed to be a result of agitating, pumping, and handling of gelcoat. Improvements to the local exhaust ventilation systems in the VEC cells should also be considered to address the potentially high short-term exposures. Regarding the noise measurements, all personal and area measurements taken in Plant 6 and 7 were below the OSHA Permissible Exposure Level (PEL) of 90 dBA. The gelcoater and gunner exposures are above the NIOSH Recommended Exposure Level (REL) and OSHA Action Level (AL) of 85 dBA. In a number of cases, measured noise levels indicated that there was great variation in workers' noise exposures. Certain phases of the job are noisier than others or there may be an impact/impulse component to the noise exposure. Sound exposure levels in Plant 6 are on average 2-4 dBA higher than the VEC plant 7 levels (an increase of 3 dB is a doubling of the sound energy). The results of the noise monitoring suggest the need for noise control of tasks that generate excessive exposures in Plant 6. If styrene and noise exposures are not reduced, the audiometric monitoring of employees that are exposed simultaneously to noise and styrene is recommended, as detailed in the ACGIH notes in its Noise Section (ACGIH, 2004).
Control-technology; Engineering-controls; Noise; Noise-exposure; Noise-levels; Styrenes; Boat-manufacturing-industry; Fibrous-dusts; Fibrous-glass; Reinforced-plastics; Region-5; Exposure-limits; Air-sampling; Ventilation-systems; Author Keywords: Fiberglass Reinforced Plastics (FRP); Gelocoat; Styrene; Boat Manufacturing; Closed Molding; Open Molding
National Institute for Occupational Safety and Health, Division of Applied Research and Technology, Engineering and Physical Hazards Branch, Mail Stop R-5, 4676 Columbia Parkway, Cincinnati, OH 45226-1998
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Field Studies; Control Technology
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Research Tools and Approaches: Control Technology and Personal Protective Equipment
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National Institute for Occupational Safety and Health
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division