The Current MDI Industrial Hygiene Data on Spray Foam

Spray application of polyurethane foam for thermal insulation of buildings represents the polyurethane application with the highest potential worker exposure to MDI. This paper reviews the existing work done to characterize the MDI exposures of the sprayed polyurethane foam workers as well as identifying several elements of an effective industrial hygiene program suggested by the existing work. In addition, areas for additional possible work are suggested. The existing work shows clearly that MDI exposures for both the sprayed foam applicator and helper can exceed both task and shift occupational exposure limits. Additional feasible engineering controls are not obvious, so control schemes based on administrative controls (work practices, establishment of “work zones” and re-entry clearance times) and personal protective equipment (respirators, gloves, and protective clothing) are necessary. Suggestions for more work in the areas of establishing re-entry clearance times and work zones as well as characterizing amine catalyst exposures are made.