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Green Building News

Waiting for EPA Action on Spray Foam Insulation

The Environmental Protection Agency has decided to review information on hazards linked to use of uncured diisocyanate compounds, keeping alive the possibility that they’ll be heavily regulated or phased out

Image Credit: Daniel Morrison

Spray polyurethane foam is magic to some advocates of energy efficient housing — but black magic to others, who say its toxic potential outweighs its considerable merits as an airtight insulator.

Debate pegged to those views, and variations of those views, rages on in many builder forums, including GBA. As the Environmental Protection Agency noted in a press release last month, though, there are certainties in the debate: the polyisocyanates in SPF, and similar compounds designed for other purposes such as sealing concrete or finishing wood floors, have long been known to cause asthma, lung damage, and even fatal reactions in people who have been overexposed or sensitized to the chemicals.

“There has been an increase in recent years in promoting the use of foams and sealants by do-it-yourself energy-conscious homeowners, and many people may now be unknowingly exposed to risks from these chemicals,” Steve Owens, assistant administrator for EPA’s Office of Chemical Safety and Pollution Prevention, recently told Environmental Building News.

Two targets: MDI and TDI

Of particular concern are SPFs intended for use by consumers, who are unlikely wear protective gear when using the products. The agency says it is considering a number of approaches designed to address the issue, including invoking the Toxic Substances Control Act (TSCA) to require that manufacturers conduct additional exposure monitoring studies for consumer products in this category, and improve their labeling and product safety information. The agency said it also might consider regulating consumer products containing one or the other of two diisocyanates in particular – methylene diphenyl diisocyanate (MDI) and toluene diisocyanate (TDI).

The EPA is targeting TDI a bit more forcefully than MDI. A summary of the EPA action in a story published by Chemical & Engineering News notes that the agency is likely to require manufacturers to notify the EPA before using TDI in consumer goods, and might work out a plan with manufacturers to phase out consumer products containing TDI altogether, or at least require companies to monitor consumer exposure to TDI.

Creating credible standards

EBN points out that the American Society for Testing and Materials (ASTM) is developing a new standard for establishing re-occupancy times in structures where SPF has been applied, taking into account product-curing rates, mixing ratios, diisocyanate and chemical by-product emissions, and other variables. Re-occupancy times cited by manufacturers, the EPA notes, range from 8 to 24 for single-component SPF and 23 to 72 hours for two-component SPF – key safety guidelines that will need independent verification.

While it is too early to tell how effective the EPA’s call to action will be, one environmental business-to-business group,, remarked that the action plan is the first to issue a data call-in for uncured MDI under the Toxic Substances Control Act, but also that the EPA required similar submissions under another TSCA provision 20 years ago “and it is not clear that that step resulted in further EPA action at that time.” Also, adds, this EPA action doesn’t indicate that MDI and TDI might be added to the TSCA’s “chemicals of concern” list, although that step had been identified in previous EPA action plans.


  1. user-978162 | | #1

    EU foam regulation
    Could someone put these discussions in the context of recent European changes in regulation of foam insulation?

  2. BUCgQBjeeH | | #2

    Polyurethanes Industry Makes Safety a Priority
    I think your article would benefit from some information about the work the polyurethanes industry has been doing to educate people about spray polyurethane foam (SPF). Safety is an industry-wide priority, and the polyurethanes industry has active product stewardship initiatives to promote safe use and handling.

    Up and down the value chain, the polyurethanes industry has been working together to educate consumers and the public about safe and appropriate handling of spray foam products. As a regulated industry, the polyurethanes industry strives to be responsive to EPA and OSHA’s guidance and will continue to engage with them on product stewardship issues going forward.

    The makers of SPF created an easy-to-navigate website,, with helpful information for homeowners and professional contractors. If you do an internet search for “spray polyurethane foam,” it’s right there on the first page.

    Also, it is important to note that “cured” polyurethane products do not fall under EPA’s chemical action plan. EPA says that “[c]ompletely cured products are fully reacted and therefore are considered to be inert and non-toxic.” Spray polyurethane foam typically cures within a set time period after it is installed.

    The action plans are principally a statement that EPA wants to collect more information on products containing uncured MDI and TDI, and they leave the door open for doing more after collecting that data. It does not mean that consumers should be concerned about professionally installed spray foam insulation.

    Please feel free to reach out if I can provide any more information.

    Marie Francis
    American Chemistry Council
    [email protected]

  3. Jesse Thompson | | #3

    Well, I'm concerned.

    We hear far too many stories of customers of spray foam installers re-entering homes immediately after application, not being warned to vacate for an appropriate interval by sales teams, children present in just foamed houses, etc.

    It's all well and good to assume that "cured" spray foam is inert, but the rare cases when it doesn't cure properly are so disastrous that it's a risk I can't recommend our clients take.

    Glueing together a building with barrels of methylene diphenyl diisocyanate, toluene diisocyanate and a large helping of toxic flame retardants is just frightening, no matter how skilled the installer.

  4. user-910182 | | #4

    Why even use spray foam???
    Being an energy auditor since 1990, I have pretty much seen it all. I always thought spray foam was the ultimate insulation but too expensive for most. Recently it is being used more often. My views on foam changed as i am finding many problems with shrinkage, non adhesion and missed areas. I took a course on using infrared cameras and the instructor as said that he has yet to find a job with out problems. As a consultant I only recommend spray foam when cellulose can't be used.

  5. NJFoam | | #5

    Proper installation
    As a spray foam contractor, I think perhaps this will bring to light some merits of skilled users of spray foam materials, and provide some differentiation between skilled, professional installers, vs. untrained installers offering lower quality products, poor quality control upon installation, and improper equipment tolerances. I have dealt with issues of odor/sensitivity, and although quite rare, working with the contractor to remedy most issues is possible. Improper proportioning of foam, and adjustments including temperature, pressure, etc. can lead to problems associated with uncured isocyanates. It's also important to note that everyone has varying degrees of sensitivity, and after working with these products for years, no-one I know has shown any sensitivity to SPF products. As a energy auditor also, I can attest to the merits of SPF in the building envelope, with the numbers to prove it. I believe the EPA discussion is perhaps moreso aimed at the widespread homeowner use of single component and kit products, available in home centers and used by less skilled installers. Such products are common with perhaps all home performance renovations.
    I also would be interested in a European comparison BTW.

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