I am looking to gather facts (although I am sure there will be a fair amount of opinions) about spray foam insulation and the health concerns associated with the install and everyday living. I mainly want to focus on closed cell but I will include the open cell as part of this topic.

The first thing that I have looked into are the different types of spray foam. So far I have come across Icynene and Polyurethane. It seems that Icynene is the open celled version and Polyurethane is the closed cell version.

Description Reference


Polyurethane foam (commonly used in foam roofing and insulation) is based on petroleum byproducts, although there are 'green' versions, made partly from soy byproducts (instead of pure petroleum), which contain less HCFC and CFC gases. All types of sprayed polyurethane foam contain millions of tiny closed cells filled with HCFC or CFC gases. A blowing agent agitates the plastics causing the bubbles to form, and the material hardens within about one minute. Sprayed polyurethane foam is inherently water resistant due to its closed cell structure.


Icynene foam is different because it is based on Castor oil (not plastics, also known as petroleum by-products) and it does not trap air in the cells. The resulting Icynene cells are open--which means no gases are trapped in the cells, so air-infiltration is possible. Due to air and vapor movement, Icynene foam does not insulate as well as closed cell foam. In contrast, closed cell foam completely traps vapors, completely blocking air migration--which enhances the insulating capacity of polyurethane foam. Icynene foam is more ideal for applications where some air or vapor must pass through the foam, while polyurethane foam completely blocks air and vapor transmission.

Now, looking at the two. My research so far brings up the following as potential health concerns.

Polyurethane Risks Reference 1 Reference 2

Isocyanates, such as MDI (methylene diphenyl diisocyanate), are highly reactive chemicals that can cause skin, eye, and lung irritation, asthma, and chemical sensitization when absorbed through the skin or inhaled.

Although this mainly focuses on application, a few 'claims' have been made that the chemicals keep getting released after the insulation and waiting periods of 36-72 hours. Reference 3

Icynene Risks Reference 4

Icynene brand, like similar brands of foam insulation, is composed of almost 50% isocyanates

Again, like the other type, we encounter isocyanates which is where we get a lot of the issues like the first one.

This bring me to my main question. Assuming that Isocyanate is the main issue and the stem of the health concerns(secondary question below in regards to that), is there an alternative spray foam product that has less health concerns? (ie. without Isocyanate or different application method) I am looking for a spray foam alternative, not just an alternative insulation. (so cellulose doesn't fit).

These are more secondary questions that don't necessarily need to be answered. Its just nice to include as much info as possible since they are all related.

  1. Most the articles I have seen have been a few years old. Not many current ones. Has the technology changed or any new advancements been made over the past couple years that make it safer or provide better insight? Any studies or expanded research would be helpful.

  2. Is there a way to test potential reactions ahead of time? Kind of like getting an allergy test? For instance, going to a week old insulation and just spending a couple hours in the room? or just touching the foam to skin to see if a reaction occurs?

  3. We have dogs and that is also a consideration. Has there been any research regarding the effects on pets that should be taken into account as well?

  4. My question assumes that Isocyanate is the main center issue with the spray foam insulation. Is it valid to assume that, or is the issue more related to a combo of chemicals or application method?

  • There are a lot of questions here, and should probably be broken out into separate questions. Apr 27, 2015 at 18:59
  • You have a lot of good questions here. However, as it exists right now, it's far too broad. Please break it down into single questions and re-ask them individually. You'll find people will be a lot more willing to tackle a single question. Apr 29, 2015 at 13:31
  • Thanks for the comments - I have updated the question with one main question. The rest are more or less secondary questions.
    – Kalel Wade
    Apr 29, 2015 at 14:19
  • about isocyanates: "present in the hardener or catalyst of polyurethane-based two-part paints. It will be dissolved by acetone and will easily penetrate your skin and most gloves. If you really need to touch it, using Butyl gloves, or (cheaper) 2 layers of latex gloves under some DIY gloves made out of PP plastic bags ― latex gloves will only protect you for few minutes, maybe even seconds)."diy.stackexchange.com/a/261345/30205 (I don't know if isocyanates are dangerous after the thing has cured)
    – JinSnow
    Nov 29, 2022 at 14:30

2 Answers 2


Spray foam insulation is a petrochemical product that is mixed on-site and blown with a blowing agent. The actual process is not great for anyone's health, which is why applicators wear protective suits. It is also exothermic, and if done incorrectly can cause a fire (rare). Additionally, if mixed incorrectly, or even in a small percentage of cases, the foam will offgas nasty stuff for a long time, rendering the house uninhabitable. I must stress that these cases are rare, but they do happen. Furthermore, fully-cured spray foam is flammable at elevated temperatures and will char and emit smoke at typical household fire temperatures.

Are there better insulations out there than spray foam? Absolutely. Spray foam is about the most expensive insulation you can get, and it is terribly mis-used most of the time, applied where its benefits are wasted. For insulating walls between stud cavities, wet-sprayed dense-packed cellulose, sprayed fiberglass (under the brand name "Spider") or mineral wool batts are better choices. For turning an attic into conditioned space, installing rigid foam boards above the roof sheathing is the preferred approach if already re-roofing. If that's not an option, then you can fill the spaces with the aforementioned choices of cellulose, fiberglass, or mineral wool batts, as long as you 1) create a ventilation channel of 2-4 inches in the rafter bays below the roof deck, 2) install a ridge vent and soffit vents that allow every rafter bay to be ventilated, 3) use an interior-side smart vapor retarder membrane such as Intello MemBrain (note: NOT a vapor barrier like polyethylene sheeting), and 4) you finish the assembly off with drywall, being careful to make the drywall layer as airtight as possible. Alternatively, you can detail the vapor retarder membrane as an air barrier and skip the drywall or use non-airtight finish materials like tongue-and-groove pine boards or something.

  • 2
    That second paragraph is entirely opinion...and not one shared by many people. Spray foams are often considered the best option when it comes to long term energy efficiency improvements.
    – DA01
    Apr 16, 2016 at 15:21

Spray foam is toxic regardless of manufacturer claims. Water-blown does not constitute safe. Read the manufacturer's SDS / Safety Data Sheet and compare them. Some tell the whole story, other's hide the truth behind 'proprietary' disclosure laws.

Everything you need to know to protect your family from the hazards associated with this insulating product is right here; https://www.epa.gov/saferchoice/spray-polyurethane-foam-spf-insulation-and-how-use-it-more-safely

Anything else will only confuse you.

  • 2
    That link is giving a 404 now Dec 12, 2021 at 16:40

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