Help Wanted: Spray Polyurethane Foam Insulation Research

Posted on by David A. Marlow, BS

walls insulated with spray polyurethane foamEnvironmentally friendly doesn’t necessarily mean worker friendly. In many cases, new “green” technologies and products have reached the market without being adequately evaluated to determine whether they pose health or safety risks to workers in manufacture, deployment, or use. Spray polyurethane foam—commonly referred to as SPF—is a case in point. Its use as insulation has been on the upswing because of the laudable aim of builders and property owners to improve energy efficiency. As popular as it has become, however, much remains unknown about spray polyurethane foam—specifically the health implications of its amines, glycols, and phosphate upon workers.

Polyurethane foam has a high R-factor (or R-value), so it resists the flow of heat and, when used as insulation, increases a building’s energy efficiency. Because of this, it has become a favorite in the world of energy-conscious construction and renovation. While better insulation clearly means less energy consumption, what’s not clear is the level of protection and ventilation workers need so that they remain safe during the installation process.

MDI: The known hazard

Spray polyurethane foam is applied as a liquid but expands as it dries. The product itself is a two-component system. The first chemical in the mixture is methylene diphenyl diisocyanate (MDI). The hazards of MDI are well-documented and their exposure limits have been established However, the known hazards for spray polyurethane foam only take into account the first part of the mixture—the MDI.

Amines, glycols, and phosphate: Unknown risks

The other half of the mix has not been studied for worker safety. It is a chemical question mark with no toxicology or health information. This part contains amines, which act as a catalyst; glycols—blowing agents that react with the foam; and phosphate, a flame retardant. This half of the spray polyurethane foam equation raises several questions:

  • What is the concentration of the fumes and vapors from these chemicals when spray foam is applied?
  • Are the workers who are applying the spray foam adequately protected?
  • What about others on site who are not applying the spray foam and who are not wearing the same personal protective equipment?
  • How long does it take to ventilate the area after application?
  • Are there cost-saving methods for isolating and venting the fumes?

A need for real-world air sampling

We are currently researching these issues. In our labs we’ve done tracer gas studies, simulating potential exposures to spray polyurethane foam components, but to make the science useful for SPF installers, we need partners to help us collect on-site air samples. At the worksite, we will collect personal breathing-zone air samples and set up five tripods with air-sampling pumps to obtain readings in a variety of sampling areas. We would like to gather samples during the spray foam application, and again at intervals afterwards. The data we collect will help us gauge:

  • The true level of personal protective equipment needed by the worker applying the spray foam and by those who are elsewhere on the worksite.
  • The actual amount of time before the area is void of harmful levels of vapors. The idea that the area needs to be clear for 24 hours is anecdotal and has no scientific underpinning.
  • Proper ventilation and cordoning of the spray foam work area. Some contractors go to great lengths to tape and plastic the room; others do nothing at all. Our air sampling will clarify what the best practice is.

Additionally, we are working on a portable spray booth that will contain overspray fumes and improve ventilation—a cost-saving intervention.

A need for solid science

It’s difficult for even the most conscientious employers to protect their workers because limited data exist on the second part of the spray foam mixture. The popularity of the product and the number of companies using it demands that there be some scientific background informing its use.

Help wanted

Please contact NIOSH to advance the science behind spray polyurethane foam insulation. You can reach us through this blog. While foam insulation may be green, with your help, our research can ensure that spray foam is sustainable for your workers as well.

—David A. Marlow, BS

Mr. Marlow is an industrial hygiene engineer in the NIOSH Division of Applied Research and Technology.


The following reports discuss the findings of this research.

In-depth survey report: spray polyurethane foam chemical exposures during spray application

In-depth survey report: spray polyurethane foam chemical exposures during spray application, Priority 1

Posted on by David A. Marlow, BS

25 comments on “Help Wanted: Spray Polyurethane Foam Insulation Research”

Comments listed below are posted by individuals not associated with CDC, unless otherwise stated. These comments do not represent the official views of CDC, and CDC does not guarantee that any information posted by individuals on this site is correct, and disclaims any liability for any loss or damage resulting from reliance on any such information. Read more about our comment policy ».

    I work with Byggmeister [], a residential remodeling firm in Newton, MA, that has been using SPF as an insulation material for some now. Your call for help is timely for us: we have recently begun to take a closer look at the existing guidelines on SPF safety in an effort to better protect our crew and our clients (most of whom are living in their homes during construction). So, we are thrilled that you are doing this research and would very much welcome the opportunity to participate in your study. Please let me know if we can be of help.

    This topic should be of interest to health and safety professionals, trades and regulatory bodies in Ireland as at the moment, there are incentive schemes in place for home owners to improve insulation in their homes. As a health and safety consultant, I closely follow such topics in the media, online etc. and am not aware of any concerns to date in this field.

    It would be interesting to hear the views of users of this material or trade representative bodies in respect of the extent of use and any research done on the application of spray polyurethane foam in Ireland.

    I think it is great you are going to research the effects of SPF on the workers, but what about the occupants. We have a year of testing that indicates our oc SPF continued to offgass. What about all of us who cannot live in our homes or the Icynene homes that are breaking down and off gassing after 6 yrs of being ‘stable’ in the home. The homeowners have no guidelines for chronic exposure to the large amount of chemicals from ‘inert’ SPF.

    It’s not just the workers that face health problems. When spray foam is not installed properly (A-B ratio is off or chemicals sprayed cold) or when it is exposed to the high heat of an attic environment it causes off-gassing of chemicals that can cause health effects after prolonged exposure. My family and I have been living this nightmare and only recently paid a large sum of money to remove our spray foam. Even following removal we cannot live in the home as we have become sensitized to the chemicals.

    Be aware that spray foam has the potential to go very wrong and when it does manufacturers and installers will use this lack of science to leave the homeowner responsible for everything.

    A few blogs are popping up explaining spray foam problems, [] and [] are good places to start.

    I just wanted to send a quick thanks regarding this posting on SPF. Glad to hear you’re looking into SPF some more. The unintended consequences of “environmentally friendly” products is quite interesting to me, mainly in how products can be “environmentally friendly” but so bad for employees using them.

    I have worked in the maritime industry quite a bit and we run into SPF there also. An added hazard of SPF in shipyards is its combustibility. Once they start, foam fires are VERY difficult to put out and emit HCN plus lots of other nasty products of combustion. Very careful protocol must be in place in order to do repair/retrofit work on ships which contain this foam. Fishing vessels commonly have SPF insulating their fish holds. This might be another industry to examine in your study.

    A very informative article and a good reminder that sometimes the end result does not always justify the means, even in the world of “green.”

    Like all things if the installer is not certified or been properly trained then you risk to have problems.The SPF industry has come along way in taking out the poor quality workmanship we have seen in the past. The fact remains that the two part chemical reaction between part A and B must be given 48 hours to finish it`s reaction in a good ventilated area, all installers should be wearing air supplied apparatus during the installation. the grey area does not exist in this process and when you use quality products and installers then you do not have a problem. The agressive market should not dictate the price of this product and I believe short cuts will disappear, that should eliminate fly by night companies giving false advice to home owners and design officials a like.

    I worked in the theatrical scenery industy for 25 years for a company with no respiratory protection program, where urethane spray foam was used constantly. The thing about spray foam is that is doesnt really have an overpowering odor, which makes one less concerned about breathing the vapors. Stronger labeling by manufacturors right on the canisters such as a big red WARNING sign would be helpful for people who are not instructed properly and the employer does not provide MSDS. In my last year at that company I developed chest pains and breathing problems so severe I thought I was going to die and did not suspect it was urethane vapors making me so ill. I can tell you for a fact that improper mixing will also somtimes emit liquids that will never solidify and leak into wood and other porous materials. Spray foam is used commonly in the theatrical industry for such things as texture,large sculpture, and other applications that it is not intended for. This might be an area for you to advertise your study.

    “what’s not clear is the level of protection and ventilation workers need so that they remain safe during the installation process.”

    I disagree and think it’s very presumptuous of you to say this. There is already plenty of documentation about the safety and precautions one must take when using spray foam insulation. In fact, one might argue that it is safer to use than fiberglass insulation.

    Fiberglass insulation has been used for ever, but it is made of fibers. Fibers that disintegrate over time and can float in the air, being breathed in by people if exposed to the area that it is found in. This can get into the lungs.

    Spray foam, on the other hand, dries solid, and therefore does not have that attribute. Additionally, those applying spray foam wear a lot of safety equipment, including suits and respirators that one would expect a scientist to be wearing if dealing with a chemical spill or radioactive material.

    I have been in the spray foam industry for over 20 years, and can honestly say that I find your claims unfounded. You do know that polyurethane foam has been used since the 1940’s, right? It was first used by the military for planes and other aviation technology. So we have years of evidence already.

    In regards to warning labels mentioned by Fred, most, if not all packaging and cans already have the warnings. Additionally, they have manuals and videos that highlight these warnings as well. I would assume that most people using spray foam insulation would already be reading these materials.

    Honestly, I think people should be more concerned about Radon than spray foam fumes. If you don’t already know about Radon, look it up. This is much more a concern and is often not known about or discussed. This is the true silent killer!

    Thank you for your comment. Although employers have taken steps over the years to reduce occupational exposures in the application of spray polyurethane foam, our present knowledge about the potential risks relates only to one component of the spray foam mixture, methylene diphenyl diisocyanate (MDI), as our blog noted. As we stated, “It’s difficult for even the most conscientious employers to protect their workers because limited data exist on the second part of the spray foam mixture.” As builders and facilities managers increasingly use spray polyurethane foam for insulation, this new knowledge will help support the safe growth of this industry.

    Spray foam insulation has so many advantages over conventional insulating methods now used in home construction. I would like to see it used especially in mobile homes where I have found that many times the batt type insulation has fallen down inside of walls due to transport.

    Greenwash it all you like, 3 percent soy doesn’t make sprayfoam “green”. As a consumer I can no longer live in my home as it is offgassing chemicals. Not to mention my family is sensitized to everyday things in the environment and almost have to live in a bubble now. Isocyanates comprise 50 % of this toxic foam and are odorless. We had it installed by a reputable company and have visited respirologists ever since. To top it off if this foam catches on fire it releases cyanide gas. Nice. Will be interesting to see in the future what lawsuits arise from this nasty invention. Sure it works well, it insulates my home, but to what cost? More research needs to be done on this. We have been in touch with experts in the US EPA and it is astounding how many families have been affected by this. Our first hand experience trumps anything that a contractor can write here… shame, shame, shame.


    Recently our firm was engaged to assist in remediating off-gassing of toxins (including confirmed Isocyanates) in a structure which had been retro fitted with SPF insulation.
    We implemented a two-part protocol which consisted of using an all ‘green’ toxin sealant on all exposed insulation combined with the installation of zero ozone producing bi-polar ionization device inserted into the HVAC system to terminate odors and toxins, and to circulate negative ions throughout the structure and behind the wall cavities.

    The results were a reduction in toxins brought to below regulatory standards of less than .20 ppb Formaldehyde and reduction in MDI below 5 ppb without removal of any drywall. As a result we are now working with some manufacturers of SPF to solve the problem in order to address the concerns of customers. Our product and this protocol also come with a warranty against reoccurrences.

    Contact us if you wish to discuss employing our methods and protocols.

    My wife and I have been experiencing severe respiratory problems and skin irritations after I had spray foam insulation installed in my NC home last year. Out of desperation and after doing some research I hired a company to come and treat my house to handle this toxic odor which began right after the insulation was foamed in.

    The company sprayed a white chemical coating called Clean Seal “DTOX” on the foam insulation and then installed a very small air purifying machine in my heat-air conditioning ductwork which runs constantan. Not sure what the little thing is they put in the ductwork but I can tell you the results are unbelievable! One day there’s a strong paint “odor” and in less than 24 hours after the company finished treating the house the odor is gone, my eyes don’t sting and my wife and had the first good night’s sleep in 6 months.

    After reading about other people having problems with similar types of foam insulation I can tell you that this treatment I had done got rid of the problem and we are very very pleased with the results. They even gave me a warranty! I recommend this procedure to everyone having the same problems with insulation.

    References to products or services do not constitute an endorsement by NIOSH or the U.S. government.

    Foam is becoming less and less useful as a wall insulator. Sure, it’s still great for lofts but newer forms of insulation exist for cavity walls that are much more effective than foam. Home Insulation is still extremely important… just make sure your get the right type fro your property.

    The extremely bad news: Polyurethane Foam (PUF) contains a chemical, TCEP, which has flame-retardant properties and has been shown to cause cancer. You can find more about this on the following location :
    [] .

    Boudewijn, what you say is the same thing i rode somewhere else on the internet recently.
    I thought it was on [].
    They said that as long as it is untouched and stable it can do no harm, but as soon at the material becomes dust due to physical change like breaking it, the particles cause cancer within a short period of time.
    I don’t know if it is true but it sounds like the same problem asbestos carries, when it becomes dust it becomes dangerous, but in an untouched stable form it can do no harm.

    (Polyurethane Foam (PUF) contains a chemical, TCEP, which has flame-retardant properties and has been shown to cause cancer. ) Exactly so……..

    Please feel free to study my house, me and my cats for your research. My attic was sprayed with SPF, I was not told to vacate nor get my pets out the day they sprayed, I ended up with horrendous chemical vapors/odors throughout my house, including on my clothing in the closet, and later learned there was a lot of off ratio foam sprayed. My pets and I were in the house the day they sprayed; that day and for 12 days after I sat paralyzed in my house because the vapors and odors were terrifying but the contractor kept telling me that everything was OK. I finally had some neutral parties who had experience with spray foam come in to examine the foam in my attic, and was told it was a sloppy job most likely done by inexperienced sprayers and that there was a lot of off ratio foam.

    I had to move out because it was causing me to have headaches, very serious eye irritation, burning in my nasal passage and sinuses and I was becoming forgetful and spaced out. Unfortunately I can’t afford to board all of my cats so there is one left in the house, and I have to keep going back in the house to feed him and get him outside for some fresh air. Needless to say, this has been about the most traumatic experience I’ve ever had; I’m afraid of my house, scared my cats have been harmed and scared of my own potential long term health problems from this exposure.

    So I’ll be glad to participate in your research.

    I wanted to thank all of you who volunteered to assist us on this project. Because of your willingness to assist in this research, we have been able proceed with our measurements of worker exposures to spray foam fumes. I look forward to sharing the results of the study when it is complete.

Comments are closed.

Post a Comment

Page last reviewed: January 20, 2022
Page last updated: January 20, 2022