Stewart Air National Guard Base, NY, C-5M Painting Refurbishment Assessment

Major Scott Steigerwald, Command Bioenvironmental Engineer, Headquarters Air National Guard Bureau, requested the USAF School of Aerospace Medicine, Consultative Services Division provide a comprehensive exposure and risk assessment of the corrosion control process conducted on the C-5M in Building 101 at Stewart Air National Guard Base, NY. This facility was previously a fuels systems maintenance facility. At the time of this assessment, the facility was being converted for depot-type refurbishment of C-5M aircraft. A health risk assessment was accomplished 24-31 July 2012 to assess spray painting operations during a C-5M refurbishment. Neither the American Conference of Industrial Hygienists nor the Occupational Safety and Health Administration (OSHA) has specified an exposure limit for hexamethylene diisocyanate (HDI) oligomers; therefore, no OSHA or American Conference of Industrial Hygienists standard was exceeded. The U.S. Air Force School of Aerospace medicine recommends using the Oregon OSHA standard for risk assessment and management. Exposures to HDI oligomers exceeded the Oregon OSHA 8-hour time-weighted average and ceiling limit standards during chine cove painting processes. Exposures to HDI oligomers exceeded the action level, 50% of the Oregon OSHA standard, during flight deck painting operations despite using water- based polyurethane paints. Therefore, respiratory protection consisting of an air-purifying respirator with organic vapor cartridges and a high-efficiency particulate pre-filter should be continued by all painters within the restricted area. Additionally, contact hazards from isocyanate paints can adequately be mitigated through the continued practice of wearing cotton or Tyvek(registered name) coveralls and nitrile or neoprene gloves.