Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, HETA 2010-0045-3129, 2011 Jun; :1-43
On January 12, 2010, NIOSH received an employer request for an HHE at a middle school in Virginia. The request was made because of staff concerns about exposure to mold in the school building. More than a dozen employees had reported health complaints they thought had been caused by mold since the school underwent renovation in 2006-2007. NIOSH investigators made a site visit on January 27-28, 2010. We randomly selected 72 (out of 137) employees for confidential medical interviews; 68 were available. In addition, three employees on medical leave and nine employees not on our list were interviewed. We observed workplace conditions and the crawl space beneath the renovated part of the building. We reviewed the HVAC system balancing reports, current HVAC operations, and consultant reports, and we evaluated the functioning of the HVAC system. We measured air pressure differentials between the classrooms and crawl space to determine which direction air was flowing between the two areas. Sticky-tape samples were collected from surfaces for microscopic fungal analysis, and vacuum dust samples were collected from furniture for cat, dog, dust mite, and cockroach allergens. Surfaces were wiped with a Swiffer® sheet and analyzed for the presence of fungal species. A meter was used to measure the interior wall moisture levels. Measurements of CO2, CO, temperature, and RH were made throughout the workday in the new and renovated classrooms. Randomly selected school employees had rates of work-related symptoms similar to or below those reported in a study of buildings not known to have IEQ problems and in the general population. Many of the nonspecific symptoms reported, such as sinus problems and headaches, are common among people working in offices and schools, as well as in the general population. More serious health problems reported by some staff are not related to working in the building. The crawl space under the renovated part of the building has a dirt floor with a partial moisture barrier, and the soil slopes toward the foundation instead of away from it, allowing water to enter the crawl space. At the time of our site visit in January 2010, there was no visible mold growth or standing water in the crawl space but there was moisture under the partial moisture barrier. The RH levels in the crawl space were higher than in the school building, and there was rust on the crawl space metal beams. In addition, the crawl space was under positive pressure, which allowed air from the crawl space to enter the school building, because the fan that generates the negative pressure (relative to the school) was not turned on. Samples taken from the new part of the school had lower fungal concentrations overall than those from the first floor of the renovated part. Significant concentrations of cat allergen were found on chairs in several classrooms and on the couch in the teachers’ lounge. Recommendations to prevent water incursion and microbial growth are provided in this report.
Molds; Microorganisms; Fungi; Allergens; Indoor-environmental-quality; Indoor-air-pollution; Relative-humidity; Ventilation; Ventilation-systems;
Author Keywords: Elementary and Secondary Schools; mold; ERMI; crawl space; cat allergen; dog allergen; IEQ; ventilation; visual contrast sensitivity; chronic biotoxin-related illness