The Signal: News and Notes from the Pharos Team

Sprayed Polyurethane Foams: An Explosive Issue

Jim Vallette April 27th, 2010 5 comments

“On a Saturday afternoon this past May, while pumping a two-part ‘GREEN’ soy-based foam into the attic ceiling of a Cape Cod home renovation, a fireball erupted, taking the hose man’s life.”

So begins a harrowing account by health and safety consultant Richard Hughes, in which he explores how a polyurethane spray foam applicator in Falmouth, Massachusetts, died on the job last year.

Sprayed polyurethane foams (SPF), especially those that contain soy-based polyols, are commonly called “green” building materials. Some people like its ability to tightly seal hard-to-access areas; others recite industry literature that trumpets the use of bio-based ingredients (soy) in the chemistry and the absence of free formaldehyde in the product.

There are multiple variations on ingredients used in SPF, but the key ones are the same. These are two part systems. One part is an isocyanate. The other part is a mix of polyols, flame-retardants, blowing agents, and other additives. Foam insulation installers follow the same basic steps that occur in industrial polyurethane factories, but in a far more confined space, combining Parts A and B in peoples’ attics.

Before the foams arrive on the job site, there are upstream hazardous associations, including reactions with formaldehyde and chlorine. Like PVC, polyurethane uses significant quantities of chlorinated compounds in its manufacture leading to emissions of dioxins and furans. These persistent, bioaccumulative toxicants are highly potent carcinogens and endocrine disruptors.

The production of methylene diphenyl diisocyanate (MDI), the most prevalent isocyanate used in SPF, requires a whole host of chemicals at various stages, including toluene, benzene, nitrobenzene, aniline, formaldehyde, methylene dianiline (MDA), and phosgene (produced from carbon monoxide and chlorine).

SPF installers combine the isocyanate (Part A) with a mixture of polyols, additives and catalysts (Part B).

Polyols are made from adipic acid, variously with ethylene glycol, propylene oxide or other chemicals. Sometimes the polyols are produced with soy, but this accounts for less than 10 percent of the final polyurethane product.

Additives include surfactants, blowing agents, and flame-retardants, some of which are known to contribute significantly to global warming and ozone depletion. (See box below for examples). Catalysts, which trigger the two-part reaction, can include problematic heavy metals. A common catalyst is lead naphthenate.

Federal agencies are starting to look much more closely at SPF. OSHA, the Consumer Products Safety Council, U.S. Environmental Protection Agency, and National Institute for Occupational Safety and Health (NIOSH), have formed a Federal SPF Workgroup. The group aims to:

  • “Improve availability of accurate and comprehensive hazard and risk information.” At a December 2009 Federal SPF Workgroup webinar, EPA official Mary Cushmac warned that do-it-yourself applicators are using two-component kits and “are often unaware of the hazards and the need to prevent skin, eye and inhalation exposures.” She raised a question that, disturbingly, remains unanswered: “When can occupants, residents, and school children safely re-enter the premises after SPF application?” The agencies said fundamental guidance is needed for "ventilation, exposure controls, clean-up, and re-entry time.”
  • “Address inaccurate or misleading marketing claims.” The federal workgroup listed such claims as “No off-gassing”, “non-toxic”, “safe”, “green”, “environmentally friendly,” “is plant-based”, and “made from soy beans.” A slide warns that the Federal Trade Commission “prohibits deceptive representation in advertising, labeling... and sales presentations.”
  • “Address exposure assessment and data gaps.” Janet Carter, an OSHA scientist, noted, “Only a few Material Safety Data Sheets mention the possible need for respiratory protection for ‘adjacent workers’… and do not mention the possible presence of MDI.”

“Worker exposures (are) not always considered in developing ‘green’ products and practices,” charged NIOSH scientist, Dr. Daniel Almaguer. “A truly comprehensive approach to sustainability and green practices needs to include occupational safety and health aspects.”

Drawing a lesson from the explosion on Cape Cod, Richard Hughes concludes, “Chemicals in the residential construction world are a far larger source for concern than we are presently acknowledging in manufacturers, distributors and our own independent safety literature.”

Even less understood than occupational hazards are long-term user exposures from chemicals released into the household from the spray application process, and from the installed foam.

The Pharos Project database now evaluates several SPF insulation products. We are adding more each week. Please sign up to take a comprehensive look at the volatile chemical mixtures that insulation applicators handle as they manufacture polyurethane, attic by attic.


Brenda Morris-Chatham, January 30th, 2014

This is just friggin hard........ got a 1853  southern plantion home bought from org. family. . No updates, however  well taken care of. 14 ft. ceilings, great in summer, winter diffrent story. Needs floors, walls all insulated. These old homes are used to breathing. Cannot find answer,any.?cotton in ga.

Jim, October 1st, 2013

I am a Fire Investigator who is doing some studies on the risks of SPF insulation and the sprayers. I've seen everything from using high heat halogen lights without covers, to smoking while spraying! I can't say what caused this fire without knowing more detail but I do know that all spray foams are not created equal!!! Some of them burn readily, and other don't! Some off gas toxic chemicals and others don't! So, it really depends on the type of foma you're testing and what you're testing for.   I'm interested in more specifics on the orifin and cause of this fire. Can you please send me any specifics that you might have? Thanks, Jim  

Insulation, December 7th, 2012

I do n ot think so people knows about this info. But things are going perfectly fine I had spray foam in 2009 and its almost 2012 end and am happy it depends which company is giving you treatement.

BUTCH , June 28th, 2010

Adobe might work in AZ or NM, however it wouldn't last a season in wet humid climates. SPF is safe as long as you follow manufacturers guidelines. I am sure the "hose Man" that died was doing something he shouldn't be doing. This could be his fault or his boss's fault for not training himproper. Not the article did not mention what foam was being sprayed. Also the article trys to encite fear by talking about 1 blowing agents that has been illegal in the US for years now. Clearly a slanted article.

Demetrio A Valdez, June 21st, 2010

We need to go back to making houses out of traditional nontoxic adobe bricks and natural lumber. Chemicals are destroying mother earth not to mention all the toxic waste generated to make this chemicals.A well build Adobe houses doesn't even need any kind of insulation, the termal value of adobes keeps a home confortable yearround.

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