Abstract
In May of 1994, the National Institute for Occupational Safety and Health (NIOSH) received a formal request for a health hazard evaluation (HHE) at the J.L. Long Middle School in Dallas, Texas. The request was from the director of health services for the Dallas Independent School District. Employees of the school reported a variety of building-related health complaints, including an elevated prevalence of physician-diagnosed asthma. On May 15, 1994, NIOSH investigators completed a site walk -through evaluation. Medical and environmental investigations were done in August of 1994. An interim NIOSH industrial hygiene report was issued on November 9, 1994. An indoor air contaminant was suspected of causing the elevated prevalence of asthma at the school. Environmental investigations completed prior to the NIOSH HETA uncovered indoor air quality (IAQ) problems and provided recommendations for improvements in the maintenance of ventilation systems and the control of potential bioaerosols. During the NIOSH walk-through evaluation, isocyanates from the roofing materials were identified as a potential exposure source; subsequent air sampling during test applications of foam roofing and sealing compounds, at a site remote from the school, revealed that the roofing/repair processes used at the school could have released isocyanates.