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Is Spray Foam Insulation Toxic?

Cured spray foam insulation when installed correctly by experienced and trained spray foam technicians with professional, maintained equipment using reputable raw materials is inert and non-toxic to the inhabitants of the building after install is complete.


It is important however to vacate the building or home during the install process for at least one day due to the off-gassing of the chemical reaction during the install process. All modern spray foam insulations as of this writing do not contain harmful substances once cured, including formaldehyde, CFCs, or HCFCs.

So under what circumstances would spray foam Insulation be toxic?

Improper chemical mixture by the spray foam installer is the number one contributing factor to spray foam insulation being either toxic or non-toxic after the install. The spray foam installer will be able to identify if the foam they are spraying is reacting well or not well and be able to identify and fix the issue before completing the project. More often then not, the most important factor when determining a favorable toxic-free outcome is by choosing a competent, reputable spray foam insulation company to complete the install. This will mitigate most all toxicity issues that should arise.

In fact, most spray foam products on the market have received the GreenGuard Gold Certification for Children & schools, highlighting its overall health and safety.

Most competent spray foam companies should be using Modern state-of-the-art equipment with built-in fail-safes to shut down production if the ratio becomes imbalance. That coupled with Graco In-Site Software and Graco Flow Meters ensure the production of high-quality, safe foam. It is important that the spray foam contractors application equipment shut off when a pressure imbalance is detected or another error has occurred. Remember,  off-ratio foam is uncured foam, which is unsafe foam.

The only other circumstance that spray foam would be toxic is during the application process itself. Spray foam insulation is made up of isocyanates and polymers resins. It is important that the spray area is masked off and a negative pressure ventilation is being used, especially in an attic space.


Negative pressure fans help mitigate and exhaust all unwanted fumes during install. Symptoms of prolonged isocyanate, or A-side, exposure include irritant of the eyes, gastrointestinal, and respiratory tracts. If contact with skin with the skin is made possible inflammation may occur. Contact with isocyanates can sensitize sensitive individuals which essentially means that if the individual comes into contact with the chemicals a second time, the above symptoms can occur including asthma attacks.

Polymer resin or B side is much less harmful and is inert in its raw form. It is composed mostly of recycled plastic resins and blowing agents. Fun fact: the blowing agent for open cell spray foam insulation is H2O (water). When open cell insulation is installed the steam from the chemical reaction is water vapor being released in the form of carbon dioxide.

Despite some manufacturers stating that you can re-enter the home as little as four hours after install, Compass always recommends that a homeowner should only re-enter the home the day after the spray foam install has been completed. Like any new product including paint, carpet, or even a new car, there will be a residual odor that typically dissipates within a couple days but can last up to a week. This is completely normal.

While not required, some people expedite the process of removing residual odors by opening windows and installing fans which blow air out of the building. 

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