Health hazard evaluation report: HETA-2003-0039-2914, Hilton Head Elementary School, Hilton Head Island, South Carolina.
Hilton Head Elementary School in Hilton Head Island, South Carolina is a pre-kindergarten to 5 th grade elementary school which consists of three interconnected buildings: the Yellow building was built in the 1970s, the Blue building in late 1980s, and the Red building in 1997. The school has a history of poorly controlled indoor relative humidity, water incursion, musty odor, and fungal contamination in ductwork. In October 2002, the National Institute for Occupational Safety and Health (NIOSH) received a confidential health hazard evaluation (HHE) request from school employees to investigate complaints of chest tightness, shortness of breath, eye irritation, allergic rhinitis, and headache and indoor air quality. In February 2003, NIOSH conducted a walk-through survey of the school. We performed a visual inspection of the school buildings and the heating, ventilating, and air-conditioning (HVAC) systems, obtained limited air and bulk samples, and administered a health questionnaire to employees with a 73% participation rate. We found that the total airborne fungal spore concentrations were lower than outdoor levels in 5-minute collection samples from 13 different locations. However, Cladosporium constituted the predominant fungal taxon in the Yellow and Blue buildings, whereas Penicillium/Aspergillus were the predominant fungal taxa in the Red building and outdoors. We identified fungal contamination, which was predominantly Cladosporium, in a bulk sample of internal ductwork insulation from the Blue building. There was a more than ten-fold increase in the airborne Cladosporium spore count in one room when a unit ventilator was turned on, suggesting fungal amplification in and dissemination from the unit ventilator. In our February 2003 survey, relative humidity ranged from 30 to 39% compared to 31 to 76% in a survey conducted from September to December 2002 by an environmental consulting firm, which the school had contracted. We measured carbon dioxide (CO2) in 26 rooms and found it ranged from 480 to 1900 parts per million parts (ppm) air by volume. In six rooms (all located in the Yellow and Blue buildings) the CO2 level exceeded the recommended limit of 1000 ppm, suggesting that the outdoor air exchange rate in these six rooms may be lower than the recommended rate of 15 cubic feet per minute per occupant. In one Yellow and one Red building room, floor water activity exceeded the 0.65 level required for growth by most microbial species. Compared to Red building employees who participated in our survey, Yellow and Blue building participants combined were about 2 times more likely to report wheeze within the last year; about 4 times more likely to report sleep broken due to breathing difficulty within the last year; about 2 times more likely to report work-related cough within the last year; about 2 times more likely to report work-related watery/itchy eyes and sore/dry throat within the last year; and about 2 times more likely to report hypersensitivity pneumonitis symptoms (fever/chills, flu-like achiness/muscle aches, or unusual tiredness). Compared to a national study of office employees, Yellow and Blue building participants were about 3 times more likely to report frequent work-related wheeze which occurred over the last month; and about 2 times more likely to report frequent work-related shortness of breath, chest tightness, and cough which occurred over the last month. Compared to national rates, Hilton Head Elementary School female participants 40 to 69 years of age who had never smoked were about 3 times more likely to report current asthma; and about 2 times more likely to report watery/itchy eye symptoms and sinus problems within the last year. We recommend that: all sources of water incursion be identified and repaired; current HVAC systems be modified to maintain relative humidity within the 30%-60% range; routine HVAC system maintenance schedules be implemented and adhered to; and ductwork insulation be inspected and removed if fungal contamination is identified. Employees should promptly report water incursion to management and should seek medical evaluation if work-related respiratory symptoms persist despite water damage and mold remediation.