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Spray-polyurethane foam (SPF) insulation, growing in popularity, is under scrutiny from EPA. What's a homeowner or builder to do?

A friend of mine used to be a long-haul truck driver. At one point he even became a trainer working with new drivers.

Over dinner recently, I asked what was one key lesson that he would want to impart to any new driver. While he was thinking about it, his wife lit up and offered this advice (which I'm sure is not from the company manual): make sure your seatbelt is removed before you begin a hot swap.

In trucking, a hot swap occurs in a truck being driven by a team of two drivers when they are in a real hurry to make a delivery. When one is ready to take a break and turn the wheel over, rather than taking the time to stop, they may decide to trade places while the vehicle is moving down the highway.

Hot swapping green building techniques

While I'm sure that experienced drivers can "hot swap" quite, um, professionally, it is an inherently unsafe practice. This is underscored by the fact that you have to remove your seatbelt, in a speeding tractor-trailer, before you can even begin!

When I heard this, it felt to me a lot like a situation we face with some regularity in green building. We are racing to make our buildings safer, healthier for occupants, less-polluting, and lower carbon. But we are behind in that race. For example, we have been paying serious attention to the health effects of building materials on indoor air quality for only about 20 years. We have been inventing new chemicals that affect our indoor air quality for well over 100 years.

Unfortunately for the builder, homeowner, or renter who simply wants some reliable advice on what to worry about from an environmental perspective, and what not to worry about, things sometimes change or crop up unexpectedly. And we're not usually completely ready with a seamless hot swap. Remember when compact fluorescent bulbs first came out? Remember the first low-flow toilets? Best forget them.

The issue of the day? SPF safety

The issue of the day is spray polyurethane foam (SPF) insulation products. Last month the U.S. Environmental Protection Agency (EPA) released a new action plan for a key family of chemicals used in SPF. Isocyanates, such as MDI (methylene diphenyl diisocyanate), are chemicals that react with polyols to form polyurethane. They can also cause skin, eye, and lung irritation, asthma, and chemical sensitization when absorbed through the skin or inhaled.
Polyurethane is in a lot of stuff, from foam mattresses to bowling balls. When it is fully reacted or "cured," it is stable and its chemistry is not a significant concern. However, Some products, however, such as adhesives, coatings, and spray foam, react while being applied by builders or homeowners doing insulation retrofits, and continue to react for some hours afterwards, and may contain "uncured" isocyanates to which people may be exposed.

This is not news: worker protection protocols and quality assurance programs for SPF installation were developed by the SPF industry decades ago. Why the fuss now?

Why the fuss now?

As Steve Owens, assistant administrator for EPA's Office of Chemical Safety and Pollution Prevention, put it, "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." You can add to that a growing number of complaints about adverse health effects from homeowners and occupants of office buildings where SPF has been applied during energy retrofits.

EPA's SPF action plan for MDI is being developed within its Design for the Environment (DfE) program under jurisdiction from the Toxic Substances Control Act (TSCA), which requires U.S. chemical manufacturers, importers, processors, and distributors to report to EPA any information suggesting that one of their chemicals "presents a substantial risk of injury to health or the environment."

While the reported data is technically public information, penetrating it is very difficult, in some measure because manufacturers often claim confidentiality for proprietary components in their chemical formulations. But the cumulative evidence to date has moved EPA to take real action on this issue, mainly to gather reports of adverse health effects from manufacturers, and to consider initial rulemaking for both consumer-applied and professionally applied SPF products.

The action plan leaves open questions about how far EPA will go to clamp down on these products, but it's safe to think of this as a shot across the bow from EPA for the SPF industry.

We don't know much about SPF offgassing

In addition to the presence of MDI in the product, the chemical reaction and curing of SPF can produce other chemicals of concern: excess isocyanates, aldehydes, amine catalysts, and other volatile organic compounds (VOCs). We don't know much about the nature and quantities of offgassing of these substances, the curing rates of SPF, or how health risks can change with improper environmental conditions or mixing ratios during the SPF process.

To that end, there is a new ASTM standard under development. John Sebrowski, a senior associate scientist with Bayer MaterialScience and chair of the task group working on this ASTM standard, is helping develop a standard practice to establish re-occupancy times after onsite SPF application. "We are currently getting ready to conduct research using micro-scale chambers and thermal desorption techniques to measure emissions," he said.

Safe re-entry times

When asked what relationship the current ASTM draft standard and research might have to the existing protocol offered by Bayer MaterialScience (which recommends re-occupancy times of 12 hours and 24 hours for workers and occupants, respectively), Sebrowski responded that the protocol would be used as a starting point, but "we are also investigating other approaches to measuring the emissions."

According to EPA, safe re-entry times put forward by manufacturers vary between 8–24 hours for one-component SPF and 23–72 hours for two-component SPF. But more research and standardized testing is clearly needed. EPA is not working alone on this issue; several other federal agencies--including the National Institute for Occupational Safety and Health, the Occupational Safety and Health Administration, and the Consumer Product Safety Commission--are part of the team. Each is concerned about protecting workers or consumers from health effects from the increasingly prevalent site-applied SPF.

Should we stop using SPF?

"I think you have to be careful when you discuss the toxicity of spray foam," says David Price, environmental scientist in the indoor environment division of EPA's Office of Air and Radiation. "I have not seen any information at this point that there is any hazard to occupants." While Price supports EPA's decision to gather data on possible post-occupancy issues with SPF, he doesn't want the public to "find the accused guilty before you hear the case."

Price has seen some of the anecdotal evidence as well as some of the scientific findings, and says that no cause-effect relationship has yet been found between SPF installation and post-occupancy illnesses. "It's appropriate for EPA to look at this stuff; that's what we do," Price said. "But I'm very sensitive about tagging a product as 'of concern' or 'may be toxic'" before the data has been gathered and reviewed.

Environmental Building News contacted several builders and foam industry professionals, and found that most were unwilling to be quoted on an issue they deemed sensitive and still-unfolding. One leading green remodeler offered this perspective: "I have stopped using SPF in any of my projects at this point. I simply can't and won't jeopardize my clients' health and the reputation of my company by using building materials with the emissions profile of SPF."

Since this news came out, comments on message boards that I have seen have tended toward defense of SPF and annoyance (that's putting it politely) at EPA. The undercurrent seems to be: Is the whole industry going to get stained because of some untrained DIYers? Let's hope that the general public doesn't jump to conclusions too rapidly--that EPA gathers its data and that its process works. And let's be real: not all SPF insulations jobs are perfect--some have even ended tragically.

Recommendations for continued use

SPF has unique advantages that can be difficult to replace. If you decide to continue using it while EPA continues its work, here are some recommendations.

Make sure that your SPF contractor installs SPF correctly, employing quality control/assurance protocols such as the following the Spray Foam Quality Control – Canadian Installation Requirements, or the ABAA Quality Assurance program.

Follow current EPA recommendations on a safe approach to installation, from the publication Quick Safety Tips for SPF Users.

If you are a homeowner or building manager or employee in a building in which SPF will be installed, follow EPA's Steps to Control Exposure.

Also, stay tuned; the SPF industry is working on a new class of SPFs--hybrid non- isocyanate polyurethanes (HPINUs)--that may pose much less serious occupant and worker health issues than our current slate of SPF building products.

What do you think about the SPF issue? Do you use it, or not? Why? Let us know below.

Tristan Roberts is Editorial Director at BuildingGreen, Inc., in Brattleboro, Vermont, which publishes information on green building solutions. Note: Peter Yost, residential program manager here, and Paula Melton, associate editor, contributed reporting to this column. Photo: Icynene's open-cell spray polyurethane foam (SPF) insulation is among the SPF industry products under scrutiny by EPA and others.

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1 There is a large and growing posted by Robert Riversong on 05/19/2011 at 01:57 pm

There is a large and growing number of anecdotal complaints about the health impacts of field-applied SFP foam, particularly low density or "open cell" proprietary urethane foams. These are without exception professionally-installed spray urethane foam insulations, not DIY projects. It's one thing to manufacture rigid foam insulations in a controlled factory environment and another thing entirely to manufacture foam insulation in situ in an uncontrolled environment with pressures to get the job done regardless of ambient temperature or relative humidity, and with the house occupants and construction workers as "canaries in the coal mine".

In far too many instances, the home-owners have had to permanently vacate their new or newly-renovated homes because of chemical sensitivity apparently initiated by the insulation. As we know from other chemical sensitizers, such as formaldehyde, initial exposure causes increased and sometimes debilitating reactions to a wide variety of chemical substances.

Aside from the logical absurdity of using petro-chemical foams to save petro-chemical energy (and the earth's climate), there are hygrodynamic reasons for avoiding relatively impermeable building materials such as plastic foam (I teach hygro-thermal engineering and building science).

It's good to hear that the EPA is finally investigating this health impact, but I would not either put much faith in their objectivity or wait for a "final" recommendation. I have long advocated using natural materials (such as borate-treated cellulose or mineral wool) for insulation as well as for other elements of residential construction (real wood or plywood rather than OSB, and felt rather than plastic housewraps, e.g.) and for building breatheable structures rather than hermetically-sealed containers.

It's past time for us "green" builders to stop accepting manufacturers' claims and apply real science and common sense to our material selections and design decisions.

2 Sprayfoam is EVIL. Make no mi posted by Mr Planet on 10/15/2011 at 07:28 pm

Sprayfoam is EVIL. Make no mistake. First, chemical compounds in anything NEVER stop offgasing. Second, it is not recyclable (Just saying it is carries no credability) I can find no such recycling station. Third, if you need to put on a safety suit to apply it, you are sadly naive to believe it will sit benignly around the structure. Fourth, it is a nonrenewable admixture...need I go on

3 We recently built a new home posted by Liss on 05/19/2011 at 01:47 pm

We recently built a new home (just LEED certified at the gold level), and the choice of insulation was one of the most difficult decisions I had to make. Our builders encouraged closed-cell spray foam, as it is the best R factor per inch of insulation. We live in Minneapolis, so we really care about that. The American Lung Association also recommends it, for a different reason: it is the best for mold prevention. After reviewing the MSDS sheets on the closed cell spray foam, I had a really hard time choosing something so toxic to workers and the environment. But in the end, none of the alternatives were compelling enough for us, so we went with spray foam. (Our installer was fully protected, just like in the picture.) I look forward to the day when the products we humans make for our homes are both effective and non-toxic, and our choices are not a trade-off between one or the other.

4 Is Icynene's foam the one tha posted by Hector on 05/19/2011 at 11:42 am

Is Icynene's foam the one that is being applied to the underside of the roof decking? I have noticed some builders are applying some type of foam to the underside of the roof decking.

5 See the guy in the Tyvek suit posted by skookum on 05/26/2011 at 02:27 pm

See the guy in the Tyvek suit spraying this stuff? Proper PPE will include a respirator and safety glasses as well, which would be burdensome and uncomfortable as shown spraying foam on a wall, but in an attic spraying rafters? or in a crawlspace? Its true that off-gassing to future occupants is an important criteria on which to grade building materials, but shouldn't the safety and comfort of the installers be at least part of the equation when consumers make these choices?

They say it you can't pronounce it you shouldn't be eating it. Maybe if even the EPA can't qualify how dangerous a product is, you shouldn't be financing the career of a person who will be breathing it because you spec'd it.

6 Very nice article although I posted by Martin on 05/16/2011 at 05:15 pm

Very nice article although I would like to have seen the "Let's hope that the general public doesn't jump to conclusions too rapidly" comment early on in the article and not at the end where many readers likely have moved on and made exactly that conclusion. Also, if the issue seems to be with DIY'ers and early occupancy, that should have been highlighter earlier on as well. Thanks again for a very informative article.

7 Isocyanates are a highly toxi posted by BEcosmart on 01/06/2012 at 04:15 am

Isocyanates are a highly toxic sensitizing chemical, responsible for documented worker deaths in the automotive industry. Spray polyurethane foam insulation, of any kind, uses isocyanates in 50% of the formulation -- even those claimed to be made with soy or other natural oils. This is not just a DIYers issue. The real issue is the improper formulation and installation of large amounts of spray foam in homes and buildings by poorly trained, unknowledgeable, or even unreputable commercial installers. Get the mixture wrong, the temperature wrong, spray too thick of a layer all at once, use a spray nozzle that hasn't been properly cleaned and maintained and you may get a bad installation and a house full of off-gassing toxic foam that will never properly cure. I personally know of at least six homeowners around the country who have had exactly this happen and they have had to evacuate their homes and find alternative living accommodations. Some of them are afraid they may never be able to occupy their home again because of the respiratory problems the isocyanates have caused now that they are sensitized. When one becomes sensitized, it essentially means there is no safe level of isocyanates your body will tolerate. When so many good alternative insulation materials are available that are truly green and have no health impacts, why take the chance of losing your home and your health by using polyurethane spray foam insulation?!

8 I built house in 2009. In jan posted by Paul on 01/31/2012 at 09:10 pm

I built house in 2009. In january of 2010 - this tangy smell started to come into my basement . It took two months to go away - i thought it glue - so i grinded floor - Then company that grinded floor - got silica over entire house - that took couple months to deal with. Then in Summer smell started again - hasnt gone away - so i had VOC test done last week - and the test found that the agent used to apply the foam is still off gassing - so if you can help please email

9 there are alternatives out there posted by Vlad on 06/04/2012 at 10:37 am

"Vacuum insulation panels (VIP) were already developed some time ago for use in appliances 

such as refrigerators and deep-freezers. Their insulation performance is a factor of five to 

eight times better than that of conventional insulation. Used in buildings they enable thin, 

highly insulating constructions to be realized for walls, roofs and floors"

10 Foam insulation posted by Karla Tuberville on 04/25/2015 at 09:17 am

We are a new home owner with the foam insulation. I have many concerns we were not told about before being put in, we live in Texas lots of humidity but we had our windows open the other night to get fresh air and our builders has now informed us that with the foam insulation you can not open the windows or it will over work the A/C the next day it also holds the humidity in the house and causes the carpet and things to be damp? Why am I putting special windows so I can enjoy the fresh air if this can not be done? I was also told when lighting my fire place I will need to crack a window so the smoke goes up the attic. Could anyone tell me who I can call to have this foam tested. Also how do I find out what the company used in the foam. We were not at our house when this was done so we have in idea if there wore special gear or not. I am very concerned and would like to know more about this. What I can do and can not do. I was also told that if something fell on your rood (tree lim) u would not now if you had damage till the would started to mold and do even more damage.
What have we done. You should be able to trust the builder on who they hire.

Thank You

11 Humidity and insulation posted by Paula Melton on 04/27/2015 at 02:04 pm

Karla, thanks for your questions. I spoke to our building science expert here, and he had the following thoughts:

1. About opening your windows: regardless of what type of insulation you use, if you have a well-insulated home, you will indeed be working your air conditioner harder if you open windows on days when it's humid outside and then trap that humid air inside. Check out this how-to guide on dehumidification in southern climates:

2. Very tight homes, regardless of the materials you use to make them airtight, are not generally compatible with burning wood in a fireplace.

3. The known risks from spray foam are for the workers who install it. You were wise to depart the premises during installation. As far as the experts know at this time, provided the spray foam cured properly after installation, occupant exposure to toxic chemicals in the foam is unlikely.

4. Many types of insulation (not just foam) absorb water and can mask the effects of a leak.

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