Health hazard evaluation report: HETA-2000-0268-2812, Southwest Airlines - San Antonio Reservations Center, San Antonio, Texas.
In April 2000, the National Institute for Occupational Safety and Health (NIOSH) received a request from the Occupational Safety and Health Administration (OSHA) for assistance in the evaluation of potential microbial contamination in the Southwest Airlines San Antonio Reservations Center (SRC), San Antonio, Texas. A similar request had been previously received by NIOSH from Southwest Airlines management. Employees in the SRC believed their health problems, which included upper respiratory infections, asthma, fatigue, headaches, chemical sensitivity, and loss of concentration and short-term memory, were related to working in this building. On June 28-30, 2000, NIOSH investigators conducted a site visit at the reservations center. A walk-through inspection was made of the building interior, exterior, and roof. Bulk material samples were collected from interior insulation in a supply duct above quadrant A, and bulk dust samples were collected on carpeted areas to assess microbial contamination. Surface samples using sticky tape were also collected beneath sinks in a women's restroom. Measurements to detect moisture incursion and general indoor air quality comfort parameters were collected, and a qualitative ventilation assessment was also performed. Confidential medical interviews were conducted to assess health concerns. Fungal concentrations from two bulk material samples of interior insulation in the supply duct above quadrant A ranged from less than the detectable limit (<758 colony forming units per gram of material [CFU/g]) to 7.1x10 4 CFU/g. Cladosporium cladosporioides was the fungi detected. Bacterial concentrations from the two bulk insulation samples were not detected (ND) (<758 CFU/g in one sample and <893 CFU/g in the other). Bulk dust samples yielded fungal levels ranging from 1.4x10 3 to 1.45x10 5 CFU/g. Pencillium, Acremonium, Cladosporium, and Alternaria alternata were the predominant fungi identified. One of the six bulk dust samples revealed increased fungal concentrations of Penicillium when compared with the other samples. Dust characterization showed samples consisted mainly of mineral crystals, skin flakes, and cellulose fibers. Sticky tape samples taken beneath the sinks in the women's restroom (closest to the break room) revealed mostly wood fibers with paint. However, fungal growth was observed in two of the five samples. This indicates that microbial growth is present. Temperatures were within the range recommended by the American Society of Heating, Refrigeration, and Air-conditioning Engineers (ASHRAE), with the exception of a few areas which varied by only 1 degree- 2 degrees F above or below the recommended range (73 degrees -79 degrees F). Relative humidity measurements were also within the range recommended by ASHRAE; however, almost half of the measurements closely approached the recommended upper limit. All carbon dioxide measurements were well below 800 parts per million (ppm), a level indicating an adequate amount of outdoor air is being supplied to the quadrant and office areas. Confidential interviews were conducted with 13 employees to assess their symptoms and health concerns. The most common symptoms reported by the employees were itchy watery eyes, runny nose, chronic sinus infections, headaches, and fatigue. Based on the information and measurements obtained during this Health Hazard Evaluation, NIOSH investigators conclude that a health hazard was not present at the time of the site visit, and that there is limited evidence of the presence of microbial growth in the SRC. There was no evidence that the health problems reported by employees were, on the whole, related to an exposure unique to the work environment. Recommendations addressing the carpet on the quadrant walls, the humidity levels, housekeeping procedures, and future water incursion incidents are included in the report.