On November 4, 2003, the National Institute for Occupational Safety and Health (NIOSH) received a request from the United Union of Roofers, Waterproofers and Allied Workers to conduct a health hazard evaluation (HHE) at US Roofing Contractors in Philadelphia, Pennsylvania. The request asked NIOSH to evaluate employee exposures to 4,4'-Methylene-bisphenyl isocyanate (MDI) during the spray application of FastTrack 100 polyurethane foam, and exposures to volatile organic compounds (VOCs) during the rubber roofing membrane installation and spray gun cleaning. The request stated that employees had reported respiratory symptoms such as difficulty breathing, coughing, chest tightness, and skin irritation, which they believe may be work related. A total of 26 full-shift, task-based, and short-term personal breathing zone (PBZ) samples for MDI and VOCs were collected on October 13, 2004 and on October 25-28, 2004. Confidential medical interviews with seven employees were completed on October 14, 2004. More than 50% of the PBZ samples for MDI exceeded the NIOSH Recommended Exposure Limit of 50 micrograms per cubic meter (microg/m3), and the NIOSH and OSHA ceiling limit of 200 microg/m3. The VOC PBZ results were all below exposure criteria. Of the seven respondents interviewed using a standard questionnaire, four reported symptoms that they attribute to FastTrack 100 exposure. These symptoms ranged in severity from stuffy nose, itchy/watery eyes, to shortness of breath and wheezing. Of the four workers reporting symptoms, three reported chest tightness, cough, sinus congestion, and shortness of breath and two workers reported headaches. One worker with no previous history of asthma reported a combination of wheezing, shortness of breath, and cough that met our case definition for presumptive work-related asthma; this worker was strongly advised to have his respiratory symptoms evaluated by his personal physician for possible occupational asthma. In the event that any worker is determined to have an MDI-associated occupational asthma, he or she must be reassigned to a job that does not involve exposure to MDI-containing materials. NIOSH investigators conclude that a health hazard exists from exposure to MDI during the polyurethane foam application. Recommendations are provided to reduce exposures to roofers during the spraying of MDI-containing foam, including respiratory protection.
Region-3; Hazard-Confirmed; Respiratory-irritants; Respiratory-protective-equipment; Respiratory-protection; Roofers; Roofing-and-sheet-metal-work; Roofing-industry; Volatiles; Organic-compounds; Personal-protective-equipment; Respiratory-system-disorders; Pulmonary-system-disorders; Bronchial-asthma