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In-depth survey report: control technology for removing lead-based paint from steel structures: chemical stripping using caustic (Peel Away ST-1) at Williams Pipeline Terminal and Station, Marshall, Minnesota.
Froehlich PA; Mickelsen RL
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, ECTB 183-15a, 1994 Nov; :1-6
These results indicate that exposures to lead and alkaline dust were well below the OSHA PELs of 50 microg/m3 for lead and 2 mg/m3 for sodium hydroxide during application of the stripping agent and wet removal of the decomposed paint. Unfortunately, the NIOSH research team was unable to observe the completion of the work. It may be assumed that brush-off blasting of the tank would have produced some lead exposure because areas of lead primer and top coat that had not been removed by the caustic stripping were observed on the tank. Cleanup of equipment and dismantling and removal of the tarp are other potential sources of lead exposure to the employees which were not documented. It is impossible to surmise what these exposures would be, therefore results of this study must be labeled inconclusive. At a subsequent survey of a highway bridge renovation, the same caustic stripper was used to remove the bulk of the lead-based paint, and abrasive blasting with coal slag was used to complete the removal. During application of the stripper and removal of the decomposed paint by scraping and rinsing, airborne concentrations of lead and caustic were well below the OSHA PELs. During blasting, lead concentrations in the 5000 microg/m3 range (100 times the PEL), were measured by personal sampling. Caustic concentrations were well below the PEL where rinsing and scraping were done, but marginally above the PEL in zones where the decomposed paint was not rinsed before blasting. This work was performed in a containment using 85 percent screening on the outside of the bridge and solid flooring suspended about 4 feet below the bridge girders. Because the blasting was performed under the bridge between the girders and bulkheads, the airborne debris during blasting was confined in volumes much smaller than the overall containment structure, thereby increasing exposure to the blasters. The concentration of lead in the bridge coating was 24 percent by weight, much greater than the 1 percent to 6 percent found on the tank.
Region-5; Control-technology; Construction-industry; Occupational-exposure; Dust-control; Dust-exposure; Paint-removers
Field Studies; Control Technology
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