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Health hazard evaluation report: HETA-2001-0067-2896, Somerset County assistance office, Somerset, Pennsylvania.
Park JH; Goe S; Choe KT; Akpinar-Elci M; Kreiss K
Morgantown, WV: 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 2001-0067-2896, 2003 Mar; :1-115
The National Institute for Occupational Safety and Health (NIOSH) received a request for a health hazard evaluation from employees of the Somerset County Assistance Office (SCAO) in November 2000. The request included health complaints (sinus infections, breathing problems, bronchial infections, chronic fatigue, muscle aches, and irritation of throat, nose and eyes) and environmental concerns about water incursion and malfunction of ventilation. At the time of the request, there had been four reported cases of hypersensitivity pneumonitis (HP) and eight reported cases of doctor-diagnosed asthma among a staff of 68 employees. In response to the request, NIOSH investigators conducted an initial walk-through survey in March 2001. The results of sample analyses and the screening questionnaire from the initial survey suggested possible biological contamination of the building and adverse respiratory effects. A second visit was planned and conducted from July 25 through August 15, 2001, to conduct environmental sampling, a heating, ventilating, and air conditioning (HVAC) inspection, medical testing, and a more extensive questionnaire survey. In December 2001, SCAO relocated their employees to a newly constructed building. The objectives of the second visit were to assess potential fungal contamination in the building and exposure levels of occupants, to characterize respiratory symptoms among occupants, to objectively test occupants' pulmonary function, and to examine the association of symptoms and medical test results with environmental exposure. For those aims, we conducted an interviewer-administered questionnaire survey, objective medical tests (spirometry and methacholines challenge tests, carbon monoxide diffusion capacity test, and exhaled nitric oxide measurements), and environmental measurements for microbial contaminants (culturable fungi, spore counts, endotoxin, ergosterol, and (1-->3)-ß-D-glucan), and evaluation of the HVAC system during the survey period. The participation rate was 93% for the screening questionnaire and 59% for the main questionnaire. There were 62 participants in the screening questionnaire survey and 15% reported asthma, 10% HP, and 36% any chest symptoms (wheeze, chest tightness, or shortness of breath in the past 4 weeks). Work-relatedness was reported by about 61% of the symptomatic people with one or more lower-respiratory symptoms (cough, wheeze, chest tightness, shortness of breath in the past 4 weeks). There were 40 participants in the main questionnaire survey and shortness of breath was reported by 52%, chest tightness by 40%, wheezing by 38%, and coughing for three consecutive months in the past 12 months by 25%. Up to 60% of the symptomatic people with the lower respiratory symptoms reported work-relatedness. Ninety-two percent of the participants in the main survey reported nasal symptoms and 90% reported sinus symptoms. In our study, we defined a case of probable work-related HP as a building occupant who reported one or more work-related (getting better away from work) lower respiratory symptoms (cough, wheeze, shortness of breath, and chest tightness) AND one or more systemic symptoms (fever/chills, flu-like/muscle achiness, weight loss of 10 pounds or more). From the questionnaire we identified 11 probable work-related HP cases. Note, however, that only 4 of these 11 symptomatic individuals were diagnosed as having HP by their physicians. We found two employees with borderline airways obstruction from our objective pulmonary function tests. One participant had mildly elevated exhaled nitric oxide. Three employees had low vital capacity with normal total lung capacity. No participants had test results indicating airways hyperresponsiveness or difficulties in gas transfer in the lungs. Our environmental investigation showed that the count of total airborne fungal spores (geometric mean=20,654 spores/m3) was about 60 times higher outdoors than indoors (geometric mean=348 spores/m3). A total of twenty fungal genera were identified in 180 indoor spore trap samples, and Cladosporium, basidiospores, and Epicoccum were the most frequently identified fungi indoors and outdoors. The level of total culturable airborne fungi (geometric mean=1,224 colony forming units (CFU)/m3) was about 10 times higher outdoors than indoors (geometric mean=123 CFU/m3). A total of 55 species of culturable fungi were identified in indoor air samples, and only 15 species were identified in outdoors samples. Both airborne spore counts and culturable fungi data showed different fungal composition between indoors and outdoors which implies that the SCAO indoor environment is likely to have had indoor sources of fungal contamination. However, we did not observe visible sources of fungal contamination within the occupied spaces at the time of investigation. Stachybotrys chartarum was found in 7 chair dust samples, but not in floor and air samples. In air, floor and chair dust samples, a total of 77 fungal species were identified, and air showed the most diverse range of fungal species. Our indoor monitoring data for relative humidity, temperature, carbon dioxide, and particles, along with bioaerosol measures, clearly showed variation of those parameters in association with human activity. Occupants were exposed to more bioaerosol and particles toward the end of the workweek. The levels of indoor carbon dioxide were lower than the recommended level (1,000 ppm, which is 700 ppm plus the outdoor level) from ASHRAE (the American Society of Heating, Refrigerating and Air-Conditioning Engineers)1; temperature during the survey period ranged from 70 to 80 degrees F and relative humidity ranged from 43 to 55%, both of which are within the recommended ranges for comfort and minimizing microbial growth (68-77oF and 30-60% relative humidity). Although our analyses were limited by a possible participation bias and by the small number of subjects participating in the study, we found a significant association of (1-->3)-ß-D-glucan level as a surrogate for fungal level in chair dust with usual cough using multivariate logistic regression analysis adjusting for age, gender, and atopic status. Airborne ergosterol, a surrogate measure for airborne fungi, was significantly associated with self-reported asthma after adjusting for gender. In our interim report on the NIOSH investigation of the HVAC system (see Appendix A), we recommended the remediation of roof leaks and problems with the HVAC system. Based on our HVAC evaluation and on the health evaluations described above, we make the following recommendations to SCAO, the previous building managers, and the SCAO employees. We recommend that the SCAO manager take the following actions: 1. Replace or clean the water-damaged furniture which may have been brought from the evaluated building to current SCAO offices. We recommend that employees take the following actions: 1. Consult a doctor for persistent or work-related lower respiratory symptoms such as wheeze, chest tightness, shortness of breath and/or cough or a combination of work-related lower respiratory symptoms and systemic symptoms (such as fever/chill, flu-like/muscle achiness, weight loss of 10 pounds or more). Objective medical tests can help your doctor diagnose the respiratory condition and its severity, and may help establish that it is work-related. We recommend that the manager of the evaluated building take the following actions to protect future tenants: 1. Fix or renovate areas with water incursion (roof, walls, and floor). Especially, repair the damaged roof to prevent condensed water from the air handling units (AHUs) from leaking through the roof. 2. Redirect the drainage from the AHU drain traps directly to the gutter, at least until the damaged roof is completely repaired. 3. Replace any water damaged building materials and water-stained carpet or ceiling tiles. 4. Inspect internal insulation linings of HVAC systems for degradation. Remove all degraded internal linings and install external insulation on the ducts with degraded internal linings that carry supply air from the AHUs. Make sure that occupants are not exposed to fibers while the internal insulation lining is removed or external insulation is applied. 5. Routinely inspect and replace the HVAC filters. Pay special attention to the main filters on AHU #3 and #4, which were inaccessible during the NIOSH inspection because the screws holding the access panels for these filters were rusted in place. Fix them to allow easy access to the filters for routine inspection. 6. Balance the HVAC system to provide appropriate air flow (15 cfm/person recommended by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE)) and outside air to all building occupants and minimize re-circulation of unfiltered plenum air introduced into the mixing boxes or the distribution chambers. 7. Confirm that all HVAC system components are functioning as programmed. 8. Inform future tenants of past problems with the building and actions taken to address them. We recommend that both SCAO and the evaluated building managers take the following actions: 1. Develop and implement a written routine inspection and preventive maintenance plan for their respective buildings to prevent recurring problems in the previous building and the new building. NIOSH environmental measurement data and analyses documented that the SCAO building is likely to have had indoor sources of microbial growth including fungi. Significant associations were observed between mold exposure in the building and self-reported asthma and cough.
Region-3; Hazards-Confirmed; Endotoxins; Indoor-air-pollution; Microorganisms; Molds; Fungi; Aerosols; Biological-agents; Respiratory-system-disorders; Respiratory-irritants; Pulmonary-system-disorders; Dusts; Ventilation-systems; Heating-systems; Organic-dusts; Indoor-environmental-quality; Author Keywords: Indoor air; bioaerosol; mold; fungi; endotoxin; ergosterol; glucan; respiratory symptoms
Field Studies; Hazard Evaluation and Technical Assistance
NTIS Accession No.
National Institute for Occupational Safety and Health
Page last reviewed: March 3, 2021
Content source: National Institute for Occupational Safety and Health Education and Information Division