The National Institute for Occupational Safety and Health (NIOSH) received a confidential request for a health hazard evaluation (HHE) from employees of the Grove Park Inn Resort and Spa (Spa), Asheville, North Carolina. The request stated that workers were experiencing chronic bronchitis and pneumonia, headaches, hoarseness, cough, sore throats, burning/watery eyes and nose, dizziness, nosebleeds, shortness of breath, nausea, inability to concentrate, sneezing, excess fatigue, fever, chills, muscle aches and dry, itchy skin, that they believed may have been related to exposure to mold and fungi in the treatment rooms and gas released from pools in the facility. In November and December 2003, NIOSH investigators conducted four site visits to evaluate the issues at the Spa. The environmental component included a moisture assessment, microbial sampling, and measurements of indoor environmental quality (IEQ) indicators (carbon dioxide [CO2], temperature, and relative humidity [RH]). Water samples were taken from pools and fountains throughout the Spa and tested for bacteria, fungi, mycobacteria, and endotoxin. Chlorine levels in the water and air were measured. The medical component included confidential interviews with employees, administration of a questionnaire, and collection of blood samples for Stachylysin, a research test that may indicate exposure to Stachybotrys chartarum. The environmental evaluation revealed elevated moisture levels that led to mold growth behind walls and above ceilings of Room 18 and the women's restroom. Microbial sampling identified a variety of fungi including Stachybotrys chartarum. Bulk water samples taken from the pool and hot tub systems revealed the presence of Mycobacterium and Gram-negative bacteria. Results of the IEQ monitoring revealed that the ventilation was adequate in supplying air and controlling CO2 levels, air temperature, and RH to within acceptable ranges. Massage therapists reported significantly more cough, achiness, sinus problems, dry or sore throat, sneezing and fatigue than did managers, who served as the referent group. Odors may have played a role in the reporting of subjective symptoms by this group of employees. Odors figure prominently in IEQ complaints, have historically guided ventilation practice, and are often used to make judgments on the healthfulness of indoor spaces. Maintenance employees, whose work included cutting into walls and other activities to identify the fungal growth, did not have a significantly higher prevalence of any work-related symptoms when compared to managers. Regarding the research test we performed, four persons had detectable concentrations of Stachylysin in their serum. Three were managers with no known exposure to the Spa or treatment Room 18. One was a maintenance employee who had been working to identify the source of moldy odors in the Spa. No massage therapists had Stachylysin detected in their serum. The Stachylysin test was performed to determine its usefulness as a biomarker of exposure to Stachybotrys chartarum, not to determine whether employees' symptoms were due to mold exposure at the Spa. The lack of detectable Stachylysin in the serum of the massage therapists could have reflected an absence of exposure, or that too much time may have elapsed since their exposure, and the Stachylysin may have cleared from the serum. It could also reflect poor test sensitivity. The positive findings in three of the managers may reflect an unidentified exposure, or it could reflect cross-reactivity with other antigens, such as common environmental fungi. NIOSH investigators found localized areas of fungal contamination in building materials in the Spa. The Spa pools and fountains had higher than anticipated levels of microbial contamination. NIOSH investigators recommend remediating the mold found in treatment rooms, monitoring moisture levels in treatment room walls, and adjusting the water disinfection program to reduce microbial levels in pools and fountains.