NIOSH Investigates Exposures to Lead, Isocyanates at Military Maintenance Facility
A recently released report from NIOSH’s Health Hazard Evaluation program details visits from agency personnel to a military maintenance facility that serviced vehicles and repaired small arms. The visits were requested by a manager at the facility who was concerned about employees’ exposures to lead in the small arms repair shop and to isocyanates in the vehicle painting shop. In the small arms shop, NIOSH collected air samples and hand wipe samples from all three employees both before and after they washed their hands. NIOSH also collected surface wipe samples and took blood samples from the three employees and nine others who worked in the shop occasionally. No lead was found in any of the personal air samples. After handwashing, the lead levels on employees’ hands ranged from 1.1 to 2.4 µg. Lead levels on regularly cleaned surfaces were low, with the highest being 19 µg/100 cm2. The firing range in the shop was found to have a turbulent airflow that could have caused unpredictable depositing of lead particles on surfaces.  One of the full-time employees in the arms repair shop had a blood lead level of 8.8 µg/dL. The employee told NIOSH investigators that he had significant non-occupational exposure to lead. The BLLs of the other employees ranged from 0.64 to 1.9 µg/dL, compared to the average adult BLL in the U.S. of 1.05 µg/dL. In the paint shop, NIOSH collected personal air samples for hexamethylene diisocyanate, or HDI. None of the samples for HDI monomer were greater than the NIOSH recommended exposure limit of 0.005 ppm or the NIOSH ceiling limit of 0.02 ppm. Personal air samples for HDI oligomer, which does not have an occupational exposure limit, ranged from 0.0025 to 0.097 mg/m3. Air samples near the spray paint booth and inside the paint preparation room did not have detectable concentrations of HDI monomer or oligomer. One employee’s blood test confirmed the presence of isophorone diisocyanate antibodies, indicating recent exposure to IPDI. 
An inspection of the ventilation system in the spray paint booth indicated that a few filters were missing or damaged. Employees in the paint spray booth told NIOSH investigators that they could not wear full-face respirators, which NIOSH recommends for this type of work, because the face shields would become covered by paint overspray. The agency’s HHE report states that disposable covers could be used to keep these surfaces clear of paint. NIOSH also found that some of the protective suits employees wore in the spray paint booth were too small, exposing the employees’ eyes and faces. The agency recommended that the employer reduce air turbulence in the firing range by maintaining air velocity between 50 and 75 feet per minute; substitute a paint that did not contain isocyanates; improve ventilation in the spray paint booth; and use properly fitted protective garments with full-facepiece supplied-air respirators in the paint shop. NIOSH also recommended that employees in the arms repair shop wear nitrile gloves during work and launder contaminated clothing on site before going home. For more information, read the full HHE report (
) on the NIOSH website.