Health Hazard Evaluation Report HETA 98-0203-2778, United Airlines, Indianapolis, Indiana.
In April 1998, the National Institute for Occupational Safety and Health (NIOSH) received a confidential employee request for a health hazard evaluation (HHE) concerning the cleaning, overhauling, and repair of aircraft lavatory tanks and hardware at the United Airlines maintenance facility in Indianapolis, Indiana. The HHE request stated that employees were concerned over potential exposures to infectious microorganisms during the cleaning of aircraft lavatories. In response to this request, an initial site visit was conducted on September 22, 1998, to look at the cleaning and overhaul processes, ventilation systems and controls, and job activities. The tanks and parts are removed, pressure-cleaned, soaked, and/or scraped, depending upon the amount of debris that is present. Environmental monitoring was conducted on April 3, 1999, which included the collection of area and/or personal breathing zone (PBZ) air samples for volatile organic compounds (VOCs), sodium hydroxide mist, and total particulates in the cleaning room and an adjacent floor board cutting area. Bulk samples of fluid in stored lavatory tanks that had been stored for two years and recently used lavatory tanks were analyzed for human enteric pathogenic bacteria. The two stored tank samples contained Corynebacterium spp., Gram-negative bacteria, and Providencia rettgeri. The recently used aircraft lavatory samples contained Morganella morganii, Providencia rettgeri, and Proteus penneri. To determine the effectiveness of the fresh toilet deodorant mixture ("blue water") to inhibit growth, inoculation/culture studies were performed. Isolates of Morganella morganii, Proteus penneri, and Providencia rettgeri from the bulk samples grew after being inoculated into the fresh toilet deodorant mixture, suggesting that some organisms are able to overcome the hostile environment created by the "blue water." The levels of total particulates and VOCs in air samples were low and were well below current occupational exposure limits. Sodium hydroxide, a major component in the soaps, was not detected in the air samples. The cleaning room was under positive pressure relative to the rest of the work area during the site visit, and there were areas of little air movement near the employees' workstations.