Exposure to Methylene Diphenyl Diisocyante (MDI) among polyurethane roof workers

Abstract

A cross-sectional study was done to evaluate the association between methylene diphenyl diisocyanate (MDI) exposure and respiratory system deterioration among permanent male workers. The studied company, located in Puerto Rico, corrects leaking and humidity problems by means of polyurethane roof insulation. Concentrations of MDI produced by the spray application of polyurethane foam were measured by personal air samples. Samples were collected by drawing a known volume of air through an impregnated glass fiber filter, contained in an open-face cassette, using OSHA Analytical Method 47 for Methylerie Diphenyl Diisocyanate. The collected concentration samples were compared to the permissible exposure limits for MDI. Both the monitoring and health symptoms of the employees served as the basis of an audit of the company's work practices and safety program. The health symptoms were assessed using a health questionnaire initially designed to evaluate the association between respiratory problems and work history only. Analysis of the cassette filters showed that all the samples were below the exposure limits established for MDI. Measurements met both the 8-hr time weight average and permissible exposure limit as a ceiling value. Personal interviews showed no association between exposure to low levels of MDI and respiratory symptoms. Their results reflected the opportunity to improve occupational hygiene by providing the workers with personal protective equipment and standardizing their work clothes.