Photograph of - damaged vinyl siding Health Effects of Vinyl Chloride Gases, Smells,Odors
US EPA / ATSDR information, part 1

  • VINYL CHLORIDE HEALTH INFORMATION - CONTENTS: Possible Hazards Associated with Vinyl Building Products, Production, Odors in Normal Use, or During Demolition, Disposal, Combustion in Fires? Exposure limits & exposure effects of vinyl chloride, Medical information and information about vinyl chloride and plastic "offgassing", Links to articles on diagnosing and curing smells in buildings. Level of Health Hazard from PVC Building Products.
  • POST a QUESTION or READ FAQs about hazards of vinyl chloride gases, smells, and odors, or about vinyl siding and other vinyl products used on buildings
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Vinyl chloride or PVC Health hazards in or at buildings or from building products: this article discusses possible health effects of exposure to vinyl-chloride (PVC - polyvinyl chloride) and hPVC and gives references to more scholarly information sources.

To improve clarity and provide public information we include here information from several US government sources including the US EPA and the US ATSDR, Department of health and Human Services, Agency for Toxic substances and Disease Registry

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Possible Hazards Associated with Vinyl Building Products, Production, Odors in Normal Use, or During Demolition, Disposal, Combustion in Fires

Vinyl siding with stains or moisture indicators (C) Daniel FriedmanArticle Contents

Plastic odors and the detection & source-diagnosis of many common odor sources observed some installations of vinyl exterior building siding or in other plastic or vinyl building products such as windows and trim are discussed


Level of Health Hazard from PVC Building Products in Residential Use

The argument about the actual level of health hazard from vinyl product odors (plastic smells) in normal residential use (such as odors from vinyl siding or windows) is ongoing.

Clearly the chief health concerns most sources cite for PVC building products such as vinyl siding appear to be health risks to the workers during production (dioxin, the most powerful carcinogenic substance known), and health risks later (HCL and dioxin) if the material is burned - say as waste or in a house fire. Dioxin is almost certainly released at harmful levels in those cases.

Disposal of PVC Building Products

Disposal of plastic building products by burial means those products are likely to remain intact for a very very long time. Disposal by burning is likely to be dangerous, releasing dangerous levels of dioxin and HCL. For disposal of vinyl products a different process, thermal depolymerization, has been developed to convert the plastic into fuel and minerals, but it's not widely used.

Plastic or PVC Odor Complaints

At some buildings occupants complain (to us by email) of odors and outgassing that is on occasion traced to vinyl siding, vinyl window products, building trim, or window screens. We suspect that suspect that the chemistry of gases may be different for each plastic-containing material. In vinyl siding or vinyl windows or trim the building material used would be uPVC or Rigid PVC.

We have not found a reliable source documenting the chemistry of such odors, but some sources cite possible outgassing of dioxin and HCL (probably at very low levels), and one unsubstantiated source (no authoritative citations) claimed formaldehyde outgassing (doubtful). Prudent avoidance may be in order from even these odors, especially for people at particular health risk, such as asthmatics or infants and the elderly. - REFERENCES

Most home inspectors do not provide environmental and odor diagnosis. But if your question is tracking down the odor source, any building occupant might be able to handle this perfectly well yourself following the odor patch test process we describe

Before blaming building siding or windows on an odor, be sure you've properly tracked down the odor source. Also

The vinyl building products industry argues that the levels of dioxin and HCL (hydrochloric acid) from their products are not significant. - REFERENCES

Vinyl Chloride Health Hazard Information - US ATSDR

Synonyms for vinyl chloride include chloroethene, chloroethylene, 1-chloroethylene, ethylene monochloride, monochloroethylene, monovinyl chloride, MVC, VC, VCM, and vinyl chloride monomer. The following is quoted from the US ATSDR.

Inhalation is the primary route of exposure, and vinyl chloride is readily absorbed from the lungs. Its odor threshold is too high to provide an adequate warning of hazardous concentrations. The odor of vinyl chloride becomes detectable at around 3,000 ppm and the OSHA PEL is 1 ppm (8-hour TWA). Therefore, workers can be overexposed to vinyl chloride without being aware of its presence. A 5-minute exposure to airborne concentrations of 8,000 ppm can cause dizziness.

As airborne levels increase to 20,000 ppm, effects can include drowsiness, loss of coordination, visual and auditory abnormalities, disorientation, nausea, headache, and burning or tingling of the extremities.

Exposure to higher concentrations of vinyl chloride for longer durations can cause death, presumably due to central nervous system (CNS) and respiratory depression. The gas is heavier than air and can cause asphyxiation in poorly ventilated or enclosed spaces.

Children exposed to the same levels of vinyl chloride as adults may receive a larger dose because they have greater lung surface area:body weight ratios and increased minute volumes:weight ratios. In addition, they may be exposed to higher levels than adults in the same location because of their short stature and the higher levels of vinyl chloride found nearer to the ground.

Reader Question: What are the health risks of vinyl siding

I bought a home two years ago that was built in the 1920's. The siding was redone, maybe 10- 15 years ago.

I've always wanted to replace the [vinyl] siding [on my home] because I was aware that there may be health risks associated to the material.

I would like to know if there really are risks to inhabitants, especially children, and what those risks are.

If it is recommended to remove the siding, what is the best way to dispose of the material? - S.V.Z.

Reply: Is Installed vinyl siding on homes a health hazard?


The principal health risks associated with vinyl siding are those that can occur during the manufacturing process and thus the hazards were or could be to workers in the siding manufacturing facilities.

Once having been installed on a home, risks to building occupants from vinyl siding or other vinyl products would occur only if the material is burned, as there could be toxic offgassing from the material in a fire.

Finally, we have received a few building odor complaints that were traced to offgassing from vinyl and other plastic products, particularly when exposed to heat and sunlight, such as odd chemical smells that we have traced not to vinyl siding products, but to certain window screen materials and to some vinyl window sashes and frames in retrofit windows.


Otherwise, the answer to your question is no. There is no health justification for removing installed vinyl siding from a building.

Should Vinyl Siding be a Removed?

We do not recommend removal of the vinyl siding on on your home unless it is badly damaged. Some early vinyl siding products have been found to be easily cracked or broken, and others to fade in color. Siding that is damaged may leak wind-driven rain into building walls and should therefore be repaired or replaced. Faded vinyl siding is only a cosmetic issue.

How Should I Dispose of Vinyl Siding Scrap or Waste Material?

When we have had to dispose of vinyl siding during construction products we have taken the material to public waste disposal sites that accept construction debris.

We have seen cases of builders who disposed of vinyl siding scraps by burying them on the building site. Not only is this prohibited in many communities, but burying a material that will not biodegrade is a poor practice that does not respect future property owners nor the environment.

Reader Question: is PVC off-gassing from replacement windows harmful?

I have been ordered by my condo association to remove my old windows and install new ones. I have asthma. are these PVC windows harmful to breathe?

- Anonymous (by private email to editor) 2016/03/14

Reply: Possibly

The off-gassing of PVC or other plastic window frames, sashes, or even screens varies considerably by product as well as by building conditions such as sun-exposure, heat sources, fresh-air makeup, and other indoor air quality hazards that may or may not be present.

There is research discussing potentially harmful effects of gases emanated from some PVC products and it seems likely that there will be PVC off-gassing at more considerable levels at manufacturing facilities. Below I'll cite some research on the toxicity of PVC off-gassing products.

Bottom line: there could be problems for an asthmatic person from PVC off-gassing but we can't say in advance what the risks will be in the case you cite as we don't know what's to be installed nor the other building conditions that have an effect on offgassing hazards.

Reader follow-up: IH Professional says there is no PVC product off-gassing

Thanks so much for taking the time to respond. your scientific support vis-a-vis the papers seems most impressive even though I've yet to examine them in detail.
I seem to be getting more confused as I go along in this troublesome sojourn. An industrial hygienist for whom i have the utmost respect whom i consulted with before your correspondence told me not to worry about the windows. He said they make the PVC windows by polymerizing vc gas and the final PVC frames have fully chemically reacted to strong covalent molecular bonds which cannot any further off gas. He said even if you drilled a hole into it it wouldn't off gas anymore. the only way it would is if you held a torch to over 212 degrees and melted it.

But Ii spoke today with a certified house preservation specialist who told me he has pictures of PVC windows sagging in the full sun after a certain period of time and ultimately coming apart. so i'm getting two very conflicting viewpoints from two very respected professionals.

I also must consider a deadline fine that could be imposed on me by the dictatorial condo association. actually my deadline was dec 1, they gave us only 3 months to get this done which I think is ridiculous!

The home preservation guy is totally sympathetic to my plight. I'm into preserving old things anyway! having once been an old car enthusiast and regardless of my asthmatic condition would much prefer to leave "the old stuff" alone.

Remember, aside from any potential PVC toxic hazard I have to concern myself with the all but assured presence of lead paint layering since this unit was built in 1962. I'm just dreading the removal of the windows fearing what might kick up so I'd like to prevent it at all costs. And talk about costs i have two units which have been priced out at $9000.00.

I just scrolled down to look at my original message to you and see it was very brief. When i first moved into my unit the windows had been painted shut so Ii took a knife and scored the paint with a damp towel around it to trap the dust. but the stupid painter actually painted the side of the frame on that thin metal strip so every time I roll the window up and down i'm abrading the dried paint and making some more airborne.

How would you recommend I deal with this ? Take the stop and sashes out and remove the metal strip or just put a chemical paint remover on it? The home preservation guy knows how to take windows out but said its a lot of work. But if I do the stripper I have to deal with the fumes and any residue of the chemical left on the metal strip

Reply: Really? More research cites off-gassing from PVC products

Your IH expert's opinion is very interesting. I certainly can't argue with a certified professional who is on-site at your property, but I'd sure like to see the supporting research for the assertion that PVC window products do not have any off-gassing concerns. The details in your report sound as if the hygienist knows the manufacture of PVC windows, yet his/her opinion does not seem to match field reports nor independent research on PVC hazards. There are research papers on PVC off-gassing for various PVC and EPVC products including windows, siding, trim, and flooring. Or perhaps s/he knows the properties of a specific PVC window product to be used at your building.

And there is no question that in actual real-life practice there have been odors traced to plastic building products including window frames, screens, and siding. We've had that confirmed by in-field inspection and even very simple testing such as the "Smell Patch Test" procedure described at

It is reasonable to speculate that variations in manufacturing process, ingredients, and methods, even within a single individual product or product line, may have on occasion produced very problematic, off-gassing products. And then there's Chinese drywall (not PVC of course), and other offshore products whose manufacture is less well understood and sometimes problematic.

I agree that NOT ALL PVC products produce problematic offgassing, and off-gassing from newer PVC-containing products indeed has, at least in some cases, been much better controlled or reduced, possibly in some cases eliminated. Still, in addition to field reports from consumers and professionals, I have personally worked on cases where there were significant offgassing / odor complaints traced to PVC products, for example at a Florida sun-porch built almost entirely of PVC materials. There have also been field reports of odor complaints traced to sun-heated plastic window screens, window frames, and vinyl siding.

I add that "sagging PVC" building components such as window frames and also plastic trim on exterior doors painted dark and exposed to heat from sunlight, particularly where a storm door is installed have certainly occurred on many buildings. We cannot state, however, the relationship between sagging plastic components damaged by heat and their off-gassing properties. One condition (sagging) does not necessarily confirm the other (offgassing rate, level, or life).

Keep in mind that we cannot possibly assert what off-gassing may occur (or not) from new products planned for use at your home and that are un-named, un-installed, and un-researched.

Regarding your concern for lead paint hazards, if there is lead paint that is to be or has been disturbed by any means there may be serious lead hazards at your building, depending on the location and amount of that material. You are correct that moving a lead-painted window sash up and down in its frame can alone produce lead dust hazards that settle on a window sill or other nearby surfaces. If this is a hazard for you it is perhaps a hazard for other owners/occupants of condos in your building and surely should be addressed by your association with the benefit of expert help.




Here are a few more studies found by searching for "Offgassing from PVC Windows"


Vinyl & Vinyl Chloride Possible Health Hazard Information - Dioxin (potent carcinogen) & HCL

The following articles provide details about the health hazards of exposure to dioxins and vinyl chloride in and around buildings:


Continue reading at VINYL CHLORIDE HEALTH HAZARDS US EPA or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


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