Reason Foam Fails #7: Unhealthy Off-Gassing & Dust

Reason Foam Fails #7:

Unhealthy Off-Gassing & Dust

Spray foam throws off two forms of toxic poison: off-gassing of the volatile organic compounds and uncured chemical dust.

Spray foam is a two-component chemical system: Part A and Part B. When the chemicals are properly prepared and precisely mixed, under the right site conditions, the chemicals will have a complete reaction eventually and become inert, ceasing to off-gas.

But off-gassing will occur indefinitely if the chemicals don't have a complete reaction because they are not properly prepared, or precisely mixed, or the site conditions are not right. Even when the application of the chemicals is done perfectly, it will off-gas during the curing process, which takes time. And while the chemicals are being sprayed with this onsite manufacturing process, there is certainly a lot of off-gassing.


When the foam is cut and trimmed as it hardens dust can be generated that contains unreacted chemicals.

Off-gassing spray foam and spray foam dust can be very dangerous. The installation worker is not wearing a hazmat suite with full face and respirator protection because it's comfortable. It's potentially dangerous for the occupants too. Occupants must stay away from the building while it cures and/or the dust remains. And, even assuming you've cleaned the dust, if the chemicals don't cure completely, the occupants may end up staying away forever.

So let's look at the dangers of off-gassing and spray foam dust - for the construction workers and the occupants. And more reasons why Foam Fails.

Why Is Off-Gassing Foam & Foam Dust Dangerous?

blog MDI

The short answer is that it's toxic! In Why Foam Fails. Reason #1: Dangerous Toxic Ingredients we noted that the high level of toxicity is well known:

The isocyanate [Part A] is typically formed from methylene diphenyl diisocyanate or MDI. MDI is a known allergen and sensitizing toxicant. From the EPA:

Diisocyanates are well known dermal and inhalation sensitizers in the workplace and have been documented to cause asthma, lung damage, and in severe cases, fatal reactions.”

Once you have been “sensitized” from exposure to MDI, even the tiniest subsequent exposure can have severe health effects.

The catalyst for the reaction/curing is often an amine compound or lead naphthenate. Amine is derived from ammonia.

From the Alliance for the Polyurethanes Industry:

“Many amine-based compounds can induce histamine liberation, which, in turn, can trigger allergic and other physiological effects, including bronchoconstriction or bronchial asthma and rhinitis.

Systemic symptoms include headache, nausea, faintness, anxiety, a decrease in blood pressure, tachycardia (rapid heartbeat), itching, erythema (reddening of the skin), urticaria (hives), and facial edema (swelling). Systemic effects (those affecting the body) that are related to the pharmacological action of amines are usually transient. Typically, there are four routes of possible or potential exposure: inhalation, skin contact, eye contact, and ingestion.”

And if you are already a chemically sensitive person - as we say in Brooklyn: Fuhgeddaboudit!

David Marllow, at the CDC noted in 2012: "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. 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..."

When homes are damaged with uncured spray foam, often the tell-tale sign is a bad odor. Too often the situation is described as an odor problem. But it's not really. Would you look at a corpse of a murder victim and say the problem was that the body smelled? Yes, the smell may be unpleasant, but the odor is just the canary signalling the potential danger. The danger is a potential poison problem.

Off-Gassing & Dust During Spray Foam Installation

During installation all occupants should be out of the building entirely. The only construction workers onsite should be the spray foam installer in a full hazmat suit with face protection, gloves, boot covers and a dedicated supply air respirator. If it is a big job site it needs to be properly partitioned to separate unprotected workers from the off gassing. The job site needs to be properly ventilated.

If these basic guidelines are not followed there can be disastrous health results. Too often families are not told to leave their home during the installation process and have acute adverse effects. As described to GreenBuildingAdvisor by Keri Rimel:

“The contractor, Deruiter Insulation, didn’t keep us out of the house at all. Our children were there when they were shooting it. We were visiting the job site, and we had meetings in the bedroom as the guy in a haz-mat suit was spraying. The Demilec rep was there on the job that day — Darren Butler from Demilec. He made a surprise visit just to tell us how great the insulation was, and how great Deruiter Insulation was. They did not ventilate at all. In fact all the windows were taped shut to keep the house warm for the next two weeks.

“Three days after they sprayed, my husband’s respiratory system shut down — his throat closed up. I thought, ‘We have a problem.’

Off-Gassing & Dust Immediately Following Spray Foam Installation

trimming sprayfoam

Not only must occupants and other workers stay off the jobsite during the spray foam installation but also immediately after. The curing takes time and until it is completely cured there is dangerous chemical off-gassing happening. The residual dust must be cleaned away before re-entry too.

So, assuming there is a complete chemical reaction of all the chemicals applied, when is it safe to re-enter the building? Of course the answer is, it depends. For example as the EPA notes:

When determining a safe re-entry time, take into consideration vulnerable populations such as children. Children may crawl, roll, or sit on surfaces (i.e., carpets and floors) and play with objects such as toys where chemical dust or residues may settle. Children with asthma are an especially vulnerable population.

The standard industry answer, per the EPA, under conditions where the chemicals fully react, appears to be that everyone should stay out for at least 24 hours, maybe up to 72 hours. And the site should be well ventilated during this period too.

Indefinite Off-Gassing From Uncured Spray Foam

And then there are the semi and fully abandoned buildings.

When a spray foam application fails to fully react the off-gassing can continue indefinitely - forcing occupants to flee indefinitely, causing not only health problems but deep financial problems as well.

One family's ordeal was the subject of a Canadian Broadcasting Corporation Marketplace segment. After an attic spray foam job failed to cure, headaches, joint pain and swelling legs and feet resulted - sending the mother to the hospital. The persistent off-gassing forced the family to live for months in a temporary trailer next to their poisoned home. To makethe home livable again they decided toremove the entire roof/attic structure from the house and rebuild an entirely new roof.

Another couple from Vermont reported to us - condensed for brevity here:

...We had a bad spray foam retrofit installation in 2016. We can't live in the home now because I became sensitized to chemicals, likely isocyanates. I developed asthma and photophobia, near non-stop headaches and nausea. I also have memory issues, as does my husband, and balance issues, which have gotten somewhat better but not completely better. I swept up the sanded foam particles that were on the stairs and in the hallway near our bed because the workers didn't clean much at all. We also met with the contractor in the home and upstairs shortly after spraying and he said it's okay to do that because the foam dries almost as soon as it's sprayed. We don't know if all the foam is bad or just sections. The contractor's insurance has denied the claim due to pollution exclusion. We've been told it's impossible to get 100% of foam out of rough timbers-main carrying beams. Humidity still causes health problems and strong odorsand it still smells bad when the sun hits the building in warm/hot weather...

Jim Vallette, of the Pharos Project - introduces us to the story of Richard Beyer of East Lyme Connecticut. Richard writes:

"A few years ago, I started taking Benadryl so I could sleep at night. I could not sleep because my skin felt like it was on fire. I suffered major headaches, heart palpitations and breathing problems. These symptoms began after we hired a company to manufacturer spray polyurethane foam (SPF) insulation in our house. The installation failed badly. Industry standards say their product is supposed to become “inert” after installation. This was not the case in my home. The SPF insulation emitted noxious odors and gases, shrunk, cracked, disappeared and literally exploded in the middle of the night. It never stopped off-gassing. Problems escalated from bad to worse. I started investigating the products more. What I found was extremely disturbing."...

These are devastating and entirely avoidable problems - brought on simply because people wanted to insulate their homes.

Avoid The Potential Problems

What's the problem? The industry and government regulators claim ignorance - we paraphrase: "We don't know what is causing what." or "The scientific evidence isn't conclusive". notes: “the potential for off-gassing of volatile chemicals from spray polyurethane foam is not fully understood and is an area where more research is needed.” The CDC, EPA and OSHA all say much more research is needed to understand what is going on also.

To add to the uncertainty, the chemical companies are quick to blame the installers. They say, "It's not the chemicals - it's improper installation!" This industry mantra reminds us of the NRA's chant -"Guns don't kill people, people kill people." To extend the metaphor, as expert Bernard Bloom notes in the CDC Marketplace segment - you're playing Russian Roulette with your property when you decide to spray foam it.

Do you feel lucky?

What are the chances? When asked how often they get odor complaints, GBA quotes a chemical manufacturing representative responding:“When we looked at the numbers, it appears to be less than one tenth of one percent..." That's a chance of about 1 in 1,000 - from the industry's mouth. Is the industry representative understating the number of incidents? Probably. So as Dirty Harry might say: "You've got to ask yourself, do you feel lucky?"

If you don't want to play Russian Roulette with your home, we suggest you not use spray foam. Less is Best. There are safe, healthy, high-performance alternatives that run zero risk of poisoning the occupants. Reach toward safe and natural high-performance building products. Let's make a healthier and less toxic world.

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