How scared should I be of spray phone insulation?

July 8, 2021 3:49 PM

I have been working from home for a year in my attic, which contains exposed spray foam insulation. How worried should I be?

The resources online about spray foam insulation health risks are mostly about proper ventilation during the installation process. There is much less information about long term effects (if any). Here’s what I can tell you:

* there are no odors and I have experienced no adverse health symptoms over the past years
* the attic is ventilated by way of a portable air conditioner and a window mounted exhaust fan.
* a couple of chunks of spray foam have been either clawed off by my cats or torn off by my children, at which point those chunks were removed from the attic and thrown out.
* I called a contractor that does spray foam insulation and he said that the spray foam binds together very hard and does not become dust, and that there is more particulate matter with fiberglass insulation than there is with foam.

I just don’t want this to be an asbestos situation where 30 years from now no one can understand why I’ve developed lung cancer. Are there any good resources on this stuff?

posted by to sir with millipedes to Home & Garden (20 answers total)

How worried should I be?

Not very.

Personally I would not worry at all about working in close proximity to polyurethane foam insulation unless it was on fire.

Chemically the stuff is pretty stable. If there are no odors, that means that residual isocyanurate monomer from the application and curing process is present only in insignificant amounts.

Unlike asbestos and fibreglass, PU foam doesn't make needle dusts that just sit there carving irritating little holes in your lungs forever. In fact it's biocompatible enough to be used in breast implants and quite capable of being broken down and eliminated once inside the body.

I would rate the cancer risk from extended work in close proximity to PU foam as lower than that from eating browned meat, i.e. down there in the bundle of things about as likely to kill me as a lightning strike during a shark attack, certainly much less dangerous than regularly walking to the shops on footpaths next to roads with cars on them.

If I found myself worrying about the long term effects of proximity to PU foam then I would rate the worry itself, rather than the PU foam, as the more likely contributor to shortening my life.
posted by flabdablet at 4:30 PM on July 8, 2021 [22 favorites]

What is making you think there's a problem?

I'm very familiar with polyurethane spray foam, mostly with its use in boats, where it's very much standard as an insulation material. I'd never heard of there being any health concerns about it.

I did a quick search after seeing this question and the first page full of links I turned up were rather dubious-looking sites that I'd be inclined to file as scaremongering. None of them cited any sources, or seemed to be clear what their specific concerns were. It seemed like they were either trying to sell some other solution, or possibly just attract people searching for a problem?

Mostly they seemed to be talking about safety aspects of the application process itself, and then rather disingenuously trying to use these to imply some sort of long term concern, without actually saying anything specific.

Don't get me wrong, the application process itself is pretty hazardous, and needs some serious equipment and protective gear.

But the stuff itself once applied is just polyurethane. You probably have a dozen other things in your house that are made of polyurethane. It's a very stable, inert, common material.

If your foam wasn't cured properly it would be soft and goopy and stink of fumes. I've seen it done wrong. It's a hell of a mess to clean up. Believe me, you'd know.
posted by automatronic at 5:07 PM on July 8, 2021 [4 favorites]

“Rigid polyurethane and polyisocyanurate foams will, when ignited, burn rapidly and produce intense heat, dense smoke and gases which are irritating, flammable and/or toxic. As with other organic [carbon based petrochemical] materials the most significant gas is usually carbon monoxide. Thermal decomposition products from polyurethane foam, consist mainly of carbon monoxide, benzene, toluene, oxides of nitrogen, hydrogen cyanide, acetaldehyde, acetone, propene, carbon dioxide, alkenes and water vapor.”

“One of, the major safety precautions to be taken around organic [carbon based petrochemical] foams is to prohibit sources of ignition such as open flames, cutting and welding torches, high intensity heat sources and smoking.”

Exposed foam sounds pretty hazardous. I'd cover with drywall.
posted by H21 at 5:40 PM on July 8, 2021

Most things are hazardous when you set them on fire, yes.

Wood, for instance, will - when ignited - burn rapidly and produce intense heat and dense smoke, as well as releasing several toxic air pollutants including benzene, formaldehyde, acrolein and various polycyclic aromatic hydrocarbons (PAHs).

You can write this scaremongering for anything. Do you consider exposed wood to be hazardous, in a home environment?

(Modern spray foams are flame retardant, incidentally. Wood isn't.)
posted by automatronic at 5:56 PM on July 8, 2021 [13 favorites]

Polyurethane foam is not intrinsically flame retardant; that property is conferred by additives.

Why are flame retardants toxic?
Studies in laboratory animals and humans have linked the most scrutinized flame retardants, called polybrominated diphenyl ethers, or PBDEs, to thyroid disruption, memory and learning problems, delayed mental and physical development, lower IQ, advanced puberty and reduced fertility.Apr 15, 2013

In world first, France bans breast implants linked to rare cancer
APRIL 4, 2019
France on Thursday became the first country to ban a type of breast implant that has been linked to a rare form of cancer.


The ban covers certain types of implants with a textured surface or polyurethane coating.

The National Agency for Medicines and Health Products (ANSM) said the ban was a "precautionary measure" taken in light of the "rare but serious danger" posed by the implants, which have been linked to anaplastic large-cell lymphoma (BIA- ALCL), a rare type of cancer that attacks the immune system.

Breast implants and cancer: Any connection? - Mayo Clinichttps://www.mayoclinic.org › faq-20057774
Aug 28, 2020
The Food and Drug Administration (FDA) has identified a possible association between breast implants and the development of anaplastic large cell lymphoma (ALCL), an uncommon cancer of the immune system. The condition is now known as breast implant-associated anaplastic large cell lymphoma (BIA-ALCL). The FDA believes that women with breast implants that have textured surfaces have a very low but increased risk of developing BIA-ALCL. However, that doesn't mean that these implants cause BIA-ALCL. Further research is needed to understand the relationship between the condition and breast implants.
...
Researchers haven't yet determined whether the type of implant — saline- or silicone-filled — affects the risk of developing BIA-ALCL but implants with textured silicone and polyurethane outer shells seem to have the highest risk. In women who have had breast implant reconstructive surgery with a textured implant the risk of developing BIA-ALCL might be as high as one in 355. In 2019, the FDA requested that the manufacturer Allergan recall specific models of its textured breast implants from the U.S. market due to the risk of BIA-ALCL. The recall also includes certain tissue expanders.

Having rough particles of polyurethane lodged deep in your lungs doesn't seem necessarily any safer than having them in breast tissue to me.
posted by jamjam at 7:29 PM on July 8, 2021

I'm not sure the breast implant diversion is particularly helpful. The "textured" Allergan implants recalled by the FDA appear to have a silicone surface capable of shedding particles into the body. From "Textured Breast Implants: A Closer Look at the Surface Debris Under the Microscope," a 2017 article:

Allergan uses a lost-salt technique to produce Biocell macro-texturing. The surface is created by dipping a chuck into uncured silicone, but before the surface dries, it is pressed into a bed of fine, granular salt and then cured in a laminar flow oven to create an irregular pattern of surface pores measuring 600 to 800 µm in diameter with depths of 150 to 200 µm.

Another manufacturer does employ polyurethane in the manufacturing process, but it's as a "sponge" used to stamp texture onto the silicone capsule. There's no indication that polyurethane remains on the textured (silicone) surface or is implanted.

Mentor uses negative-contact polyurethane foam to stamp its Siltex breast implant surfaces. Specifically, a chuck is dipped into uncured silicone to form the shell after which the uncured silicone shell is pressed into polyurethane foam to imprint pores measuring 70 to 150 µm in diameter and 40 to 100 µm in height.

Which is to say, there isn't a super strong link to concerns about polyurethane in your lungs here. Do I feel great about the idea of "rough particles of polyurethane lodged deep in [my] lungs?" Nope, I definitely do not, but we don't even have evidence that exposed spray foam insulation sheds a lot of particles, let alone particles with the correct physical properties to wind up deep in human lungs.

That said, I believe building codes usually require a thermal/ignition barrier, like 1/2 inch gypsum board, separating it from occupied spaces in the structure, and this is also the recommendation of the manufacutrers. You should drywall the room so you don't die in a house fire.
posted by pullayup at 8:06 PM on July 8, 2021 [2 favorites]

I would go so far as to agree that grinding up chunks of spray foam before huffing the resulting dust is probably ill-advised.

If chunks of spray foam have been broken off by cats, there's going to be much more cat dander in your lungs than spray foam dust.
posted by flabdablet at 8:10 PM on July 8, 2021 [3 favorites]

Oh, and when you're putting up your drywall, wear a respirator. Gypsum dust is almost certainly a less healthy thing to huff than spray foam dust.
posted by flabdablet at 8:12 PM on July 8, 2021 [3 favorites]

I have spray foam in my house. I like it a lot. I haven't drywalled over it yet because I need another can of foam and you can't get it while everyone's doing renovations.
I'd far rather deal with it than fiberglass, and I'm much more tolerant of fiberglass than most people.
But look at it this way: some plastics off-gas various substances. Some do more than others, and foam does very little.
The off-gassing declines rapidly with time - at first it's a lot, but it declines until it's not measurable. I stayed in my house the night I foamed about 200 sq ft of wall. I could smell it a bit. By now its probably down to a millionth of that, if there's anything at all.
Plastics are stable over long periods of time because they don't change very much. They're stable, and don't release much. Foam has very little in it that doesn't react and become inert.
If it's been in place for longer than a couple of weeks I wouldn't worry about it at all.
If it bothers you, staple a rug over it, or maps or wrapping paper.
posted by AugustusCrunch at 10:56 PM on July 8, 2021

Gypsum dust is almost certainly a less healthy thing to huff than spray foam dust.

That's nonsense:

Weanling and 9 months or older rats were exposed to particles of an aged (PUF I) or freshly prepared (PUF II) rigid polyurethane foam by intratracheal intubation. The dose was 5 mg of particles. The response of the lung tissue was examined morphologically by serial sacrifices. Inflammation and macrophage activity were the initial responses. Fibrosis developed after 6 months. Nodular scars and perifocal emphysema were seen after 12 months. Four rats had a papillary adenoma in a major bronchus after 18 months exposure to PUF I.

Gypsum on the other hand, from a MSDS:

Potential Acute Health Effects:
Slightly hazardous in case of inhalation (lung irritant). Slightly hazardous in case of skin contact (irritant), of eye contact (irritant), of ingestion, .

And a case where a worker was buried in Gypsum powder:

Gypsum is a mineral dust consisting of calcium sulfate and is commonly used in building construction. We here report the first case of an acute calcium sulfate aspiration.

An accidental avalanche of fine gypsum powder covered entirely a silo worker. He aspirated a large amount of gypsum powder without loosing consciousness. At admission to the emergency department the patient was breathing spontaneously and directly underwent emergency bronchoscopy. Acute tracheobronchitis was diagnosed. Remaining calcium sulfate was removed by aspiration without rinsing with additional water in order to avoid further exothermic damage to the bronchial mucosa from chemical reactions. He received steroid treatment and antibiotics, as well as bronchodilatative therapy in an attempt to increase mucociliary clearance. Within a month the patient was symptomfree without any residual radiological or functional impairment.

This unusual aspiration accident is to our knowledge the first case report of an accidental calcium sulfate aspiration. Our treatment choice left the patient without residual pulmonary impairment.

posted by jamjam at 11:12 PM on July 8, 2021

Okay, so deliberately stuffing small animals' lungs with PUF dust via tracheal tube five days per week for six weeks, then leaving all that dust in place for six months while periodically clipping out bits of lung for analysis, has worse outcomes than rapid emergency treatment to remove as much gypsum dust as possible as quickly as possible after a single exposure to it has caused acute tracheobronchitis. Good to know.

I note in passing that PUF doesn't make any dust unless you abrade or cut it.
posted by flabdablet at 2:34 AM on July 9, 2021 [4 favorites]

jamjam, are you actually familiar with polyurethane spray foam? It is not dusty stuff. It has a hard, slightly glossy outer surface. It's quite impact absorbent. If you hit it, the surface will often remain intact but dented and the foam underneath will crumple. If you cut or tear into it, it comes out in lumps that stay together.

It's really quite hard to turn it into dust. I sometimes remove it with a wire wheel on an angle grinder, and it still mostly just turns into large crumbs rather than airborne dust.

"I found a study where this stuff was shown to have toxic effects inside the body" is not the same as "I found evidence that this stuff is not safe to have in your home", unless there is also evidence of the material being likely to get from A to B.
posted by automatronic at 2:40 AM on July 9, 2021 [3 favorites]

I have not certainly not lived in very many homes where I'm at risk of having an aqueous suspension of PUF dust forcibly intubated every day for weeks on end (that being the only way to get dust of a suitably dangerous particle size suitably dangerously deep into the lungs).

However, if that did ever happen I'd still be less worried about the irritant effects of the dust than about being serially sacrificed by the intubater.
posted by flabdablet at 3:15 AM on July 9, 2021

As I understand aspiration, Flabdablet, the best possible aspiration can only clear the larger and medium bronchi, leaving the finer bronchi and alveoli virtually undisturbed. The point of the article is that the worker's lungs cleared themselves of a very substantial gypsum powder burden within a month. This cannot happen with polyurethane because it's not biodegradable. And you don't want anything in your lungs which is not biodegradable. The reason fiberglass is so much less dangerous than asbestos is that over a ten year period or so the human body can dissolve glass fibers, but not asbestos fibers.

Even if there were to be no polyurethane dust at all, automatronic, which ignores any potential rodent activity, since the rats which got into my basement chewed and stripped some away to make nests out of, the toxic fire retardants discussed in my first link are volatiles which leak out of the foam over time even when it's completely undisturbed.
posted by jamjam at 3:28 AM on July 9, 2021

And not only that, automatronic and flabdablet, polyurethane foam is short-lived because it is degraded by heat, oxygen and humidity, causing it to yellow and crumble:

A new insight into the degradation of polyurethane (PUR) slabstock foams is suggested by studying historical design objects and PUR references submitted to natural ageing. PUR foams are segregated structures comprising hard and soft domains, as well as chemical and physical crosslinking (H-bonds). H-bonds have been commonly followed in polymerisation studies of PUR foams by monitoring carbonyl bands in the infrared. Their fundamental role in PUR physical properties has been stressed; however, their liability to natural ageing has been poorly focused, with few studies suggesting their vulnerability to high temperature and humidity. As PUR has a short lifespan, and many objects show severe degradation signs (yellowing, crumbling and brittleness), the in-depth analysis of PUR foams behaviour upon natural ageing ....

posted by jamjam at 3:42 AM on July 9, 2021

jamjam, I don't know how to explain to you that finding some text that says negative-sounding things about polyurethane and pasting it in this thread, is not the same as presenting evidence that spray foam is unsafe to have present in your home.

The text you just pasted is talking about slabstock foam. The sort you buy in blocks and cut and install, not spray on. Slabstock is produced and used differently. The types I'm familiar with usually have a foil coating on each side, and have sawn edges where the open-cell structure is exposed. Slabs can't have their foam structure sealed against the substrate surface like spray foam can, and they don't get the protective hard skin that spray foam has when it's cured in-situ.

I've seen plenty of spray foam that's 20 or 30 years old. It's not crumbling into pieces. It's not turning into dust. It may be a bit yellower, but it's pretty darn yellow when it's new too.

Do you have any actual experience with the material, or are you just googling for things that sound scary about it?
posted by automatronic at 9:17 AM on July 9, 2021 [1 favorite]

No actual evidence has yet been provided that there's actually anything for OP to worry about given their particular situation. I've read a bunch of labels, looked for studies, and read through some of the literature.

Don't put it in a bong and smoke it.

[TW: Sprayfoam self harm]

I did find a fun article that states: "A literature review revealed one definite case of attempted suicide, one possible attempt by ingestion of Builders PU expandable foam and one accidental non fatal injection of such foam into the lower urinary tract."

So don't do that either.
posted by aspersioncast at 9:26 AM on July 9, 2021

The point of the article is that the worker's lungs cleared themselves of a very substantial gypsum powder burden within a month. This cannot happen with polyurethane because it's not biodegradable.
...
And not only that, automatronic and flabdablet, polyurethane foam is short-lived because it is degraded by heat, oxygen and humidity...

Lungs, of course, being well known for their lack of heat, oxygen and humidity.

This new learning amazes me, Sir Bedevere.
posted by flabdablet at 11:01 PM on July 11, 2021

Lungs, of course, being well known for their lack of heat, oxygen and humidity.


The part of the article I quoted in my comment specifies exactly what pathway the degradation of the polyurethane foam takes, flabdablet:

and many objects show severe degradation signs (yellowing, crumbling and brittleness),

It crumbles into a fine powder, which is precisely the form which caused the lung damage in the rats which were exposed to it:

Weanling and 9 months or older rats were exposed to particles of an aged (PUF I) or freshly prepared (PUF II) rigid polyurethane foam by intratracheal intubation. The dose was 5 mg of particles. The response of the lung tissue was examined morphologically by serial sacrifices. Inflammation and macrophage activity were the initial responses. Fibrosis developed after 6 months. Nodular scars and perifocal emphysema were seen after 12 months. Four rats had a papillary adenoma in a major bronchus after 18 months exposure to PUF I.

The degraded foam is not cleared from the lungs, it causes tumors, scarring, and emphysema there! Not only that, but scarring and inflammation caused by the textured polyurethane foam breast implants are exactly what is thought to have caused the BIA-ALCL lymphomas in some women!

And you, for reasons which have nothing to do with the truth -- and everything to do with not being wrong at any cost -- are trying to spin that into a desirable feature!
posted by jamjam at 1:15 AM on July 12, 2021

OP, I can only recommend basing your conclusions about the study that jamjam linked above on a careful reading of its whole text rather than jamjam's repeated quoting of its abstract.

It's pretty clear, to me at least, that the rats in the study were subjected to concentrations of PUF dust pushed deep into their lungs that are vastly in excess of what could reasonably be expected to shed spontaneously from spray foam insulation, even exposed rather than hidden behind drywall, even with help from cats and children.

It needs to be understood that this is one of a series of studies intended to investigate the consequences of insulation installation workers being repeatedly exposed to PUF dusts caused by cutting PUF blocks - i.e. the kind of slabstock foam that automatronic mentioned above - in the course of their work. Accordingly, the foam dust used in the studies was prepared from blocks. No mention is made at any point of spray foam, whose application does not involve cutting, generates no dust, and results in a skin on the foam with very good crumble resistance.

The study itself notes that "the intubation obviously introduces larger particles into the lung which probably would not have occurred by the inhalation route of exposure". It also talks about biodegradation of PUF particles within the lungs.

My rather snarky "Sir Bedevere" comment above was intended to point out the contradiction between jamjam's statement that PUF isn't biodegradable and the almost immediate followup that it does degrade from heat, humidity and oxygen.

The study mentions the mechanisms by which PUF does biodegrade in the lungs by the action of macrophages, and notes that "The response of the lung to polyurethane particles is not unique. One can state that it is the typical lesion seen after exposure to a variety of particulate matter. In this connection it might be more important to focus on the role of the macrophage breakdown products than on the chemical nature of the particle."

So unless your attic is dusty enough to make you cough and wheeze every time you go in there, I struggle to see the relevance of this rat intubation study to the question you asked about spray foam.
posted by flabdablet at 3:40 AM on July 12, 2021 [1 favorite]