Tom Lent | April 19, 2011
Last week the US EPA put the building industry on notice that it is planning steps to protect the public from asthma and other respiratory problems from two of the fundamental building blocks of polyurethane.
Methylene Diphenyl Diisocyanate (MDI) and Toluene Diisocyanate (TDI) join a growing list of EPA Chemicals of Concern that are widely used in building materials, including phthalates in vinyl flooring, bisphenol A in epoxies, HBCD and PBDE flame retardants in foam insulation, PFCs in carpet stain treatments and more (All are listed in the Pharos description of current EPA Chemicals of Concern). Action Plans on each of these describe serious health risks for the general public and outline possible voluntary and regulatory steps the EPA is considering to protect public health.
The EPA expressed particular concern for hazards from the growing use of MDI and TDI compounds in spray foams, adhesives and coatings. The polyurethane compounds made from MDI and TDI are considered relatively inert and benign. But mixing up and site-applying these products in the building instead of in a controlled factory setting can lead to major exposures to the raw uncured and hazardous diisocyanates for workers during installation and for building occupants for anywhere from days to months afterwards.
All of the spray polyurethane foam insulations in Pharos currently use these diisocyanates, adding to the dangers of sprayed polyurethanes that we've reported on earlier in this blog.
MDI & TDI are also found in products in the Pharos listings for polyurethane carpet backings, MDF and wheatboards and some recycled rubber floorings which aren't as likely to have major quantities of uncured diisocyanates but cause serious toxic exposure problems for the factory workers who make these products. According to the EPA, isocyanate exposure is the leading cause of work-related asthma.
Watch for the EPA Chemicals of Concern red attribute flag in product profiles as you select products in Pharos or use the EPA Chemicals of Concern filter to avoid all products containing any of the targeted chemicals.