--- title: Why Does Spray Foam Insulation Off-Gas? description: You've heard spray foam insulation has toxic off-gassing fumes. Is it true? Learn what off-gassing is, why it happens, and how long spray foam can off-gas. image: https://scsfoam.com/hubfs/Why%20Does%20Spray%20Foam%20Off-Gas.jpg --- [Skip to main content](https://scsfoam.com/blog/why-does-spray-foam-insulation-off-gas#maincontent) [(717) 895-3498](tel:7178953498) [![South Central Services Insulation](https://scsfoam.com/hs-fs/hubfs/branding/Website%20Logo%20Classic.png?width=900&height=300&name=Website%20Logo%20Classic.png) ![South Central Services Insulation](https://scsfoam.com/hs-fs/hubfs/branding/Website%20Logo%20White.png?width=900&height=300&name=Website%20Logo%20White.png)](https://scsfoam.com/) [Our Service Areas](https://scsfoam.com/our-services-areas) Pricing - [Our Rates](https://scsfoam.com/our-rates) - [Calculators](https://scsfoam.com/pricing-calculators) - [Financing](https://scsfoam.com/financing-options/) - [Rebates](https://scsfoam.com/rebates) [Our Team](https://scsfoam.com/our-team) Services - Residential Insulation - [Attic Insulation](https://scsfoam.com/attic-insulation) - [Basement Insulation](https://scsfoam.com/basement-insulation) - [Crawl Space Repair](https://scsfoam.com/crawl-space-encapsulation) - [Commercial Spray Foam](https://scsfoam.com/commercial-spray-foam/) - [New Construction Insulation](https://scsfoam.com/new-home-construction-insulation/) - [Pole Building Insulation](https://scsfoam.com/pole-building-insulation) - [Air-Sealing](https://scsfoam.com/air-sealing) - [Blower Door Tests](https://scsfoam.com/blower-door-tests) [Our Products](https://scsfoam.com/our-products) Learning Center - [Learning Center](https://scsfoam.com/learning-center) - [Downloadable Resources](https://scsfoam.com/downloadable-resources) - [FAQ](https://scsfoam.com/faq/) Open Search [Get A Quote](https://scsfoam.com/contact/) Search for topics or resources Enter your search below and hit enter or click the search icon. 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September 18th, 2023 2 min read By [Kilian Agha](https://scsfoam.com/blog/author/kilian-agha) ![](https://scsfoam.com/hubfs/Why%20Does%20Spray%20Foam%20Off-Gas.jpg) You were excited about spray foam as an insulation option. Then, you heard something about toxic fumes. You haven’t written off spray foam yet, but you have questions that must be answered. Does spray foam really off-gas toxic fumes? How long will it off-gas? Can I prevent it from off-gassing? Could off-gassing fumes harm my family? South Central Services has installed spray foam insulation in hundreds of homes in and around Chambersburg, PA. As the contractors applying the foam, we take the necessary precautions to protect ourselves from off-gassing fumes. We know the science behind off-gassing and would like to share that information with you. By the end of this article, you will understand: - What off-gassing is - Why off-gassing happens - How long off-gassing can occur > Don't have time to read right now? Check out [everything you need to know at a glance](https://scsfoam.com/hubfs/At%20A%20Glance/Why%20Does%20Spray%20Foam%20Insulation%20Off-Gas.pdf). ## What Is Off-Gassing? Off-gassing is the release of [volatile organic compounds (VOCs)](https://www.epa.gov/indoor-air-quality-iaq/what-are-volatile-organic-compounds-vocs) and other chemicals into the air. Off-gassing is a byproduct of a chemical reaction. When a chemical reaction occurs to form polyurethane plastic products, off-gassing naturally occurs. > [          View this post on Instagram                      ](https://www.instagram.com/reel/DBePrLWxTkP/?utm_source=ig_embed&utm_campaign=loading) > > [A post shared by South Central Services Insulation (@scsfoam)](https://www.instagram.com/reel/DBePrLWxTkP/?utm_source=ig_embed&utm_campaign=loading) Off-gassing is more common than you might think. Polyurethane can be found in the soles of your shoes, in your car seats, and in your memory foam mattress. New car smell and new shoe smell are technically off-gassing fumes. When purchasing a new memory foam mattress, manufacturers recommend letting the mattress air out for a day before anyone sleeps on it. Right after being manufactured, products created from chemical reactions will off-gas. > Does the common occurrence of off-gassing mean it is okay to inhale? No. Off-gassing fumes are toxic. In significant quantities, that toxicity can cause [respiratory problems](https://www.lung.org/clean-air/at-home/indoor-air-pollutants/volatile-organic-compounds). ## Why Does Spray Foam Off-Gas? Since spray polyurethane foam is created from a chemical reaction, off-gassing will occur. The finished spray foam product cannot be made without the byproducts of heat and off-gassing fumes. Chemical reactions are science experiments. You cannot change variables in the experiment and expect the same result. Chemical reactions create byproducts in addition to the end goal products. You cannot change how a product is made to avoid certain byproducts, at least in the case of spray foam. For polyurethane manufacturing, off-gassing is a byproduct. Below is a diagram of the chemical reaction that creates spray foam. ![Chemical Reaction to Create Foam](https://scsfoam.com/hs-fs/hubfs/Chemical%20Reaction%20to%20Create%20Foam.png?width=678&height=508&name=Chemical%20Reaction%20to%20Create%20Foam.png) Off-gassing during manufacturing cannot be avoided. To protect themselves while installing spray foam, contractors wear respirators and other [personal protective equipment (PPE)](https://scsfoam.com/blog/personal-protective-equipment-for-spray-foam-insulation-contractors). Residents and pets are asked to vacate while buildings are sprayed for their [health and safety](https://scsfoam.com/blog/is-spray-foam-bad-for-your-health). ## How Long Can Off-Gassing Occur? For spray foam installed [on-ratio](https://scsfoam.com/blog/spray-foam-insulation-glossary#on-ratio-foam-definition) within manufacturer guidelines, off-gassing will stop after 24 hours. Off-gassing does not stop at 24 hours because 24 is a magical number, but because there’s only a byproduct due to the chemical reaction. When the reaction stops, the product and byproducts cannot be created anymore. A day after the reaction has stopped, the product is cured and the byproducts have dissipated. For spray foam that is installed [off-ratio](https://scsfoam.com/blog/spray-foam-insulation-glossary#off-ratio-foam-definition), off-gassing could continue indefinitely if some amount of one chemical is left over without anything to react with. ## The Bottom Line About Off-Gassing and Spray Foam Insulation Spray polyurethane foam will off-gas as a byproduct of manufacturing. As long as the foam was installed on-ratio and within manufacturer guidelines, all of the chemicals in the reaction are gone. Off-gassing will stop after 24 hours. The spray foam product is stable and poses no health risks at this point. Now that you understand how off-gassing is related to spray foam, your next step is to: - [Learn more about spray foam failure and how to avoid it](https://scsfoam.com/blog/spray-foam-insulation-fail) - [Discover how spray foam insulation is made](https://scsfoam.com/blog/how-spray-foam-insulation-is-made) - [Find out what to look for in a reliable spray foam contractor](https://scsfoam.com/blog/how-to-choose-a-spray-foam-insulation-contractor) [![Schedule My Free Site Visit](https://no-cache.hubspot.com/cta/default/39735758/interactive-129467076199.png)](https://scsfoam.com/hs/cta/wi/redirect?encryptedPayload=AVxigLKRkASwIc%2B%2B1QTZ7mhugn9YrHwODVw8IV8Wtp83hC2Z3bnftj15iunHlSt9eVwgBZb1kQJNHsKz2IFDR0jeehSd6AmIhN%2FNNKMHscj7ozVaE%2B9dyVwoEuxa7AZ0TRVYH%2BU2ngdZKz5m6vAu%2BGj3MwFX8VYYG9aHzCgIOQOQBkE%3D&webInteractiveContentId=129467076199&portalId=39735758) *Disclaimer: While we strive to publish information accurate to building science, local building codes and standards supersede our recommendations.* [Kilian Agha](https://scsfoam.com/blog/author/kilian-agha) Kilian has co-owned and operated South Central Services for 8 years. He is passionate about community involvement. In his spare time, he enjoys being with his family, playing ice hockey, and going fishing with friends. Topics: [Building Science](https://scsfoam.com/blog/topic/building-science) [Fundamentals](https://scsfoam.com/blog/topic/fundamentals) Don't forget to share this post: ## Related Articles ### [Top 3 Places To Insulate In An Existing Home June 9th, 2025|5 min read](https://scsfoam.com/blog/top-places-to-insulate-in-an-existing-home) ### [What Is A Blower Door Test Used For? May 16th, 2025|2 min read](https://scsfoam.com/blog/what-are-blower-door-tests-used-for) ### [How Does Insulation Keep A House Cool? April 23rd, 2025|3 min read](https://scsfoam.com/blog/how-does-insulation-keep-a-house-cool) ### [What Is The R-Value Of Blown-In Insulation? April 4th, 2025|3 min read](https://scsfoam.com/blog/what-is-blown-in-insulation-r-value) ### [Can Insulation Be Reused? 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