Health Hazard Evaluation Report, HETA-99-0196-2860, Future Aviation, Inc., Naples, Florida.
On April 30, 1999, the National Institute for Occupational Safety and Health (NIOSH) received a management request for a health hazard evaluation (HHE) at Future Aviation, Inc., in Naples, Florida. The request asked NIOSH to determine if workplace exposures are related to health problems reportedly experienced by some employees. Health problems identified in the request included headaches and eye irritation. Potential exposures included emissions from isocyanate containing paints and polyurethane packing foam, and cleaning solvents during cleaning, repairing, and reassembling aircraft parts. On June 16-17, 1999, NIOSH investigators conducted an initial site visit at Future Aviation, Inc. The purpose of this site visit was to inspect the facility, observe work practices and chemical handling activities, and monitor exposures to selected workplace compounds. On June 17, 1999, full-shift personal breathing zone (PBZ) samples for petroleum solvents were collected on five workers. A 1.5 hour activity-specific PBZ sample was also collected on one worker while he cleaned a wheel hub with solvent in a wash tank. Bulk samples were collected from both wash tanks in the Test Area, and work practices, including the use of personal protective equipment, were observed. Safety procedures, policies, and employee training programs were also reviewed. Local exhaust ventilation systems at various workstations were evaluated. All exposures were below the applicable NIOSH Recommended Exposure Limit (REL) on the day of the monitoring. The highest full-shift total hydrocarbon concentration (57.1 milligrams per cubic meter [mg/m3]) was from the worker cleaning generators in the Test Area. The highest total hydrocarbon concentration (211.5 mg/m3) was measured on the worker cleaning the wheel hub. The NIOSH REL for total hydrocarbon is 350 mg/m3 as a full-shift time-weighted average. On October 19, 1999, a follow-up site visit was conducted to measure exposure to isocyanate-containing compounds during the spray painting and foam packaging operations. Two PBZ exposure measurements were collected from the painter. No 1,6-hexamethylene diisocyanate (HDI) monomer was detected, and the HDI-based polyisocyanate exposures were 10.7 and 5.1 micrograms per cubic meter of air ( g/m3). HDI monomer was detected in only one of the seven area air samples collected during spray painting; a concentration of 0.4 g/m3 was found at the curing oven doors. Also, HDI-based polyisocyanate concentrations were below the minimum detectable concentration (MDC) of 1.6 g/m3 in the area air samples. Foam packaging occurred three times during the October sampling. A 10-minute PBZ exposure measurement was collected each time the foam system was used. The foamer's 4,4'-diphenylmethane diisocyanate (MDI) exposures were 3.5 g/m3, 5.2 g/m3, and "none detected" (< 2.6 g/m3). MDI-based polyisocyanate was not detected in any sample. In an attempt to determine the worst-case exposure, a single (serial) sample was collected in the foamer's breathing zone only when MDI was being dispensed. These sampling times included short samples during each of the three packaging jobs, and a one-minute period that began when the gun malfunctioned and a small volume of MDI spilled into a box. The results of this sampling indicate an average peak exposure of 7.5 g/m3. All these exposure concentrations are well below the NIOSH REL of 200 g/m3 as a 10-minute ceiling limit. Neither MDI nor MDI-based polyisocyanates were detected at any of four area-sample locations near the foam packaging station. Personal protection programs were found to be deficient in certain areas. Gloves were not cleaned properly or maintained in an appropriate manner. Air purifying respirators were worn by a number of employees although a respirator program had not been established and exposure information had not been obtained. Recommendations in this report include implementing a comprehensive personal protection equipment program. Local exhaust ventilation was found to be sufficient; however, work practices at the Varsol hood negated the efficiency of the hood. Recommendations include reducing the pressure in the Varsol spray gun to less than 30 pounds per square inch to minimize over spray. All measured exposures were below applicable NIOSH limits. Minimizing skin contact with the polyurethane foam used in the shipping and receiving department is encouraged. Recommendations regarding the use of personal protective equipment (glove use, eye protection, respiratory protection, hearing conservation) are in the Recommendations section of this report. Engineering controls (e.g., containment, ventilation) or work practice changes (eliminating use of compressed air, depressurization, etc.) should be a first consideration to reduce the potential for exposure.