Asbestos exposure risk from minor vs. significant damage to an asbestos-containing floor covering:
What is the actual risk level from various types of damage to asphalt asbestos floor tiles, vinyl asbestos floor tiles, or asbestos-backed sheet flooring?
How much or what sort of asbestos-flooring damage require special cleaning, testing, or remediation?
This article series describes the probable risks of asbestos exposure from asbestos-containing floor tiles or sheet flooring as depending on the condition, covering, and location of the floor. Page top photo: many loose asbestos-containing floor tiles in an area like the one we show mean that there is a risk of harmful airborne asbestos that is sufficient that proper cleanup is needed. But a minor cut or scratch on a floor is a very different situation.
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A small nick or scratch on intact, secure, otherwise un-damaged asbestos suspect flooring such as shown in our photo does not require expensive nor scary "asbestos abatement" procedures.
Asbestos is safe and legal to remain in homes or public buildings as long as the asbestos materials are in good condition and the asbestos can not be released into the air. - US EPA
[Click to enlarge any image]
Where an asbestos-suspect floor hazard does indeed exist in a private home as well as in other buildings is when
and potentially when
Researching indoor airborne asbestos hazards from building floors does not find scholarly, expert reports that a private home’s kitchen or den un-disturbed (that is not ground, chopped, etc) asbestos-floor covering in good condition produces measurable levels of airborne asbestos.
Both research and my own anecdotal evidence from having spoken with people who worked in shipyards or industry where high levels of asbestos exposure occurred describe a work atmosphere that was sometimes so thick with airborne dust including asbestos that the air became opaque.
The most frequent and serious asbestos-related illnesses such as mesothelioma occurred in workers from industry where the exposure was very high or sometimes in their homes into which workers un-knowingly imported high levels of asbestos-dust on their clothing.
Beyond those industrial settings, research found potential asbestos hazards in schools that merited regulation of in-place asbestos flooring, most likely because of the situation I described above, high risk population (children spending lots of time in the building), and floors whose surface was abraded by foot traffic or by cleaning methods.
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Below you will find questions and answers previously posted on this page at its page bottom reader comment box.
A contractor drilled two .5 or .75 in holes in asbestos vinyl sheet flooring in a small half bath (20% according to lab). What is the likely extent of the risk/exposure and how long? Thanks! - 2012/12/23 James Matthews
Reply: How to Calculate the Potential Volume of Airborne Asbestos Dust Produced by Drilling Holes into Resililent Sheet Flooring with an Asbestos Backer
James,
The total volume of asbestos-containing flooring represented by the two holes you describe, if we assume for sake of calculation is 1/8" thick, is given as the sum of the volume of two cylinders of 0.5" and 0.75" in diameter and 0.125" in height.
1. Calculate the volume of asbestos-containing flooring material cut, ground, chopped, drilled
Calculating the volume of those cylinders (using Volume V = π x r2 x h ) gives us
V1 = 3.1416 x (.25)2 x 0.125 = 0.0245 cu.in.
and
V2 = 3.1416 x (.375)2 x 0.125 = 0.055 cu.in.V1 + V2 = 0.0795 cubic inches or less than 1 tenth of a cubic inch of airborne material, of which only a much smaller percentage might actually be asbestos fibers.
2. Calculate the volume of asbestos material in the disturbed debris
The most-common source of asbestos in vinyl sheet flooring is in the paper-like backer that might be 20 to 70 % asbestos by volume.
If we assume (for sake of calculation) that the flooring backer makes up 75% of the total flooring thickness, then
The volume of flooring that was cut by your drilling contractor, or 0.0795 cubic inches, might contain
0.0795 (volume of material) x .75 (portion of volume represented by the backer) x .20 (your test found 0.20 or 20% asbestos while 0.70 or 70% is the maximum plausible level of asbestos in a backer) = 0.0119 cubic inches of asbestos.
That's one hundredth of one cubic inch of asbestos as the maximum possible volume of material produced by the drilling of the two holes you describe.
Further it is unlikely that the particles produced by drilling into resilient flooring are all small, easily-airborne bits, as drilling flooring usually produces mostly larger spiral like pieces.
So the likely volume of airborne material produced by the contractor's drilling activity is likely to be a much smaller amount than the one hundredth of a cubic inch of dust.
3. Calculate the air volume of the occupied space into which asbestos dust is dispersed
You don’t give the size or dimensions of your building nor of the room where the flooring was installed, but if for illustration we pretend that the room was 10 feet x 20 feet in size or 200 square feet and had an 8 foot high ceiling, then the volume of the room in cubic feet would be 1,600 cubic feet, or (1,600 x 1728 cubic inches per cubic foot) = 2,764,800 cubic inches.
If we assume a completely uniform distribution of 100% of the drilling dust dust (which more likely would be just about 5 % of the total dust given mostly larger particle sizes produced by drilling into resilient vinyl type flooring) and if we assume NO dust control, wiping, etc., then we have
0.01 cubic inches of dust dispersed in 2,764,800 cubic inches of space in the room, or a distribution of 0.01 / 2,764,800 per cubic inch or about 0.00000625 cubic inches of dust per cubic foot of air.
Given that the volume occupied by one typical airborne asbestos fiber is measured in microns (1 inch = 25,400 microns) it’s reasonable to estimate (roughly) that there is would be less than 0.001 fibers per cubic foot of air or one fiber in 1 fiber in one thousand cubic feet.
4. Compare airborne dust total quantity dispersed with asbestos permissible exposure limits or PELs
In the U.S. OSHA sets the PEL for airborne asbestos as:
Permissible Exposure Limit (PEL) for asbestos is 0.1 fiber per cubic centimeter of air as an eight-hour time-weighted average (TWA), with an excursion limit (EL) of 1.0 asbestos fibers per cubic centimeter over a 30-minute period.
- source: ASBESTOS OSHA FACT SHEET [PDF] retrieved 2019/12/24 original source - OSHA www.osha.gov/Publications/OSHA3507.pdf
Since one cubic foot contains 28,317 ccs or cubic centimeters, the OSHA standard means that in the workplace the PEL is 0.1 x 28,317 or 2,832 fibers per cubic foot of air.
5. Estimate maximum possible airborne asbestos level & exposure
Bottom line: so how much airborne asbestos dust could have been detected in your air at the point of maximum dispersal?
If as I estimated drilling could at most have produced 0.00000625 cubic inches of dust per cubic foot of air or less than 1 fiber per cubic foot, we’re looking at a theoretical maximum asbestos dust level in your theoretical room of 1/2832 fibers or about 1 three-thousandths of the allowable exposure limit for a 30 minute period.
Sorry but we can't say more about the actual level and duration of exposure nor the actual health risk of the activity you described except to say that the dust produced by the drilling you described is likely to be well below the limits of detection in the building and certainly well below the OSHA industrial workplace standard.
A professional, CIH or certified industrial hygienist may have a different view.
Remodeling a house it was built in 1957 and it has the green tile I was cutting a piece of drywall and I didn't have a piece of wood under the drywall therefore it was a 4-inch 4ft piece that I trimmed lightly and I hit the asbestos tile the supposedly asbestos tile I'm not sure if they are or not anyway
I vacated the premises wet down the area took a shower and got rid of my clothes I'm not sure if this is too extreme but
I wasn't sure exactly what to do in the situation what is your recommendation for appearing or showing up to this residence in the future here 2017-08-15 George
Reply: What are the risks of minor damage to an asbestos-suspect floor tile or sheet flooring covering?
George,
Thank you for asking an important question that for other readers I re-phrase as
What is the level of risk from asbestos-suspect flooring that suffers a scratch or similar minor damage, and what should I do about such flooring.
There is no reasonable chance that a scratch or cut into the surface of asbestos-suspect floor tile or sheet flooring using a smooth sharp-edged blade like a drywall knife is going to create a measurable level of airborne asbestos in the building, much less a hazardous level of airborne asbestos.
Asbestos is safe and legal to remain in homes or public buildings as long as the asbestos materials are in good condition and the asbestos can not be released into the air. - US EPA
It is more than a concern that very frightening articles about asbestos-hazards can lead to great fear over situations that present no hazard. For that case there are both monetary costs and stress from worry that can be both harmful and unnecessary.
The fear of asbestos is exacerbated both by the normal worry that arises about something we think is dangerous and that we cannot see (so we fear it is beyond our control and that it sneaks up on us) and also by the preying on public fear by some companies who reap profit by providing testing or “asbestos spill cleanup” services that in some cases were not appropriate.
So what should you do if you slice into an asbestos-suspect floor surface with a drywall knife?
- Wipe up dust: Damp wipe the scratch with a damp paper towel or rag, then throw that into the trash.
- Seal: When the floor is dry, you might elect to apply a light coating of spray or other shellac (I’ve also used a cotton swab) to seal the scratch and make the floor look smooth and shiny again.
Experts advise that the safest way to stop potential asbestos hazards from an asbestos containing or asbestos-suspect floor tile or sheet flooring covering is to leave the existing floor in place, covering it over with a new layer of flooring.
Asbestos is not like radioactive materials: it does not and cannot send up harmful materials through a layer that covers the floor surface.
For situations where you must defer installing a new layer of flooring over an intact, essentially un-damaged asbestos-suspect floor tile or sheet flooring, I’ve described a successful approach using an epoxy floor sealant covered with a clear-coat to provide a durable walking surface that cannot release particles from the floor below.
See ASBESTOS FLOORING LEFT IN PLACE for details.
ASBESTOS FLOORING HAZARD REDUCTION for a description of all of the approaches to preventing a hazard form asbestos-containing floor coverings.
Hi. I have a question about asbestos in floor tile and its removal. I work at a public school and the school had a contractor come in to remove some flooring that was starting to "buckle up" in some areas due to water seeping underneath it. When the contractor came I happened to be around and I asked him before he started if the tile could be asbestos (the school was built in 1952).
He looked at it and said it wasn't 9x9 inch, and he wasn't sure what was underneath it yet, so he couldn't say for sure.
When I started at the school I was made aware by my boss that there is asbestos tile underneath the carpet in the classrooms, but he didn't mention the hallways, where this work was going to be done.
I kept a watch on the contractors as they were removing the tile flooring, (I stayed a safe distance from them...like outside the building through a window). I noticed they used no masks and there was no plastic barriers put up inside the building. They were breaking the tile up though because I noticed them shoveling it up and putting it in the big 55 gallon plastic barrels used for garbage.
They stayed for about 2 days doing this. When they were done they left these filled barrels of the tile for us to dump! I didn't want to be involved at all in their dumping! My boss came though and he said he needed my help in dumping the barrels in the outside container for garbage.
I REALLY wanted nothing to do with this and I panicked inside. I was afraid though to ask about its safety. When we went outside to dump them I kept my distance as much as possible.
When we dumped the first barrel I held my breath and we dumped it quickly and a HUGE bunch of dust went into the air.
I stepped far away and let the dust clear. I then asked if he had any kind of face mask. He did, but only the N95 kind. I put two on and some goggles. We then dumped the rest.
My question is, what are the chances that the flooring contained asbestos, and if it did, wouldn't the contractor and our head supervisor that ordered the work know about the flooring? - Mike 8/22/11
Reply:
Mike
No one can say just from text whether or not the floor tile that was taken up contained asbestos, though the lack of dust control and personal protection sounds to me like an amateur was doing the job. Even non-asbestos-containing dust can be hazardous, especially at acute exposure levels.
From the age of the school (1952) some asbestos containing materials would be expected to be present in lots of items, especially floor tiles. And the contractor's assertion that only 9" floor tiles contain asbestos is incorrect.
- ask your doctor for an opinion about your health and exposure to demolition dust that might have contained asbestos and any respiratory health complaints you may have
- if there is remaining dust or remaining examples of the same flooring they can be tested for asbestos
- building management can make be sure all of the demolition dust has been properly cleaned and removed - if it's asbestos-containing, a higher level of cleaning and post-cleanup testing are needed.
- Don't do more demolition without a competent risk assessment
And for your question of whether or not the contractor would or would not know if the floor contained asbestos?
My OPINION (not a lawyer) is that the contractor is legally obligated to be competent to perform the work for which s/he is hired; at a school, and removing flooring, that should include the ability to recognize a "red flag" that would stop the job until an asbestos hazard assessment has been made by a professional.
Faced with very high costs of an asbestos cleanup, and worried about causing a (perhaps inappropriate) panic among parents of school children, building managers I've met have sometimes opted for an "ignorance is bliss" argument.At a large Jewish Community Center in New York where it was patently obvious that there was asbestos-containing pipe insulation and flooring, the building management showed me a "report" asserting that the building was "asbestos free". The report authors simply stayed out of building areas where asbestos found.
I was pulling up some carpet in my basement today and found that there is tile on the floor beneath it. That didn't seem like a problem to me except in one corner the tile came up with the carpet and there is a green tile beneath that.
The house was built in 1950. should I be concerned that the green tile has asbesto in it? The tile broke into pieces. - Don Mac 9/5/11
Reply:
Don from the age of materials you describe it's a good chance you have one or more layers of asbestos containing floor tiles, though of course I can only speculate with so little information.
However if the floor is covered with additional layers of tile or even carpeting, it's unlikely that it is being disturbed enough to produce a detectable level of asbestos (from that source) in the building air or dust.
A single piece or two of broken tiles are not measurable; what you want to avoid is demolition making a big dusty mess.
Search our site for "How to Reduce the Hazard Floor Tiles That May Contain Asbestos" or "ASBESTOS FLOORING HAZARD REDUCTION" to read about procedures for handling the flooring.
I purchased a co-op built in the 1950's. I need to put down a new floor. The last layer of flooring is green 9x9 vinyl tiles. The pattern looks close to seneca white but the background is light green with dark green pattern. There is black tarry stuff underneath.
The tiles are extremely thin. I ripped out the tiles and the plywood underneath them in the corner about 18" square. The super told me to leave it alone as it might be asbestos, but all the contractors who have seen them, seem not to be worried about ripping up the tiles. I would feel better to play it safe and just floor over them. How do I e-mail a picture to you? - Jeanie in Queens NY 11/13/2011
I have a early 60's home with both bathrooms having what appears to be a solid surface material poured over a greenish felt. The flooring is tan with colored flecks in it throughout. I have looked for the material but haven't found any info. Does anyone know what it is? Is it possible that this material contains asbestos? - Dan 1/10/12
the tile in the place I work appears to be asbestos tile. there are some squares that are damaged, and appear to be chipped out. there are small particles, chunks, etc. in the place where the tiles are missing. is this a danger to us? - Lynn 1/12/12
I want to renovate this ranch soon and am not sure what the tile is and who do I call? I want to renovate this ranch soon and am not sure what the tile is and who do I call?Ceiling tile is from 1940 - Jo 2/7/2012
I have an old ranch home w/ sheet lino.x2 layers, over OSB board, over another type of flooring over old hardwood. From what I can see so far. The hardwood has blunt square ends, and is about 3-4" wide and appears to have paint on it. I know there is some rot in that area and would need replacing from reclaimed wood.
My question is what is the best way to remove all the lino and OSB and floor below that to get to the hardwood? I know it's going to be labor intensive but not sure how to go about it. - Tracey 2/13/2012
Utility room floor installed 1971 is Armstrong Excelon vinyl asbestos place and press tiles. Some of the tiles are loose. they are whole..just loose. Please recommend what glue to use to re-install them. - Anne 2/13/2012
I work at a Petland Discounts location that's over 20 years old. I've gotten severe breathing problems at this store. The floor polishing company comes in and polishes the floor every month and there is this thick dust in the air and then it gets all over the products. I am concerned that it contains asbestos. There are also many broken tiles in the store. - Despina 5/22/2012
In my kitchen we have a sub floor, then asbestos tiles, then another sub floor and then a layer of linoleum flooring down.
We want to lay another floor down but our floor is already up an inch with everything on it. We want to removed the whole flooring but have no clue how we should go about doing this without getting the asbestos in the air.
It is also laid in our hallway and our whole basement. Thank you so much for any help you can provide. - Gigi - 6/11/2012
I was going to put new ceramic tiles in the kitchen floor, but when I removed the transition between the wood floor and ceramic tiles I saw vinyl tiles under the kitchen floor. My question is how I would know that the vinyl tiles are asbestos or not? - Mike 7/10/2012
i removed floor tiles by hand that look very similar to some of the ones you have pictured on your web site about 9 years ago. basically i used an old grill spatula to peel them up off of the cement floor. i did use a dust mask but i was unaware at the time that some older floor tiles contain asbestos. do i have anything to worry about? - Joe 8/1/2012
Hello I scraped up a tile floor in my house and I now fear that it was asbestos. The backing is black not white. It did not grind to dust, but it came off in pieces. The floor is covered in the black backing still and I don't know how I should remove this.
Should I be concerned about removing this part? Also I suspect these tiles continue into another room under a rug. I would like to remove them eventually if possible. What do you recommend? - Mandy 10/29/2012
My husband and his family were doing some remodeling on a home we just bought (built in the 1930's).
When I stopped by the house i saw that they had ripped out the old flooring in the kitchen and bathroom. Underneath the old carpet and flooring were 9x9 squares that were on top of the original hardwoods.
I freaked out because i remembered hearing something about 9x9 tiles and asbestos on hgtv. These squares are black, but they are flexible, almost like a thick paper or a cardboard rather than a hard tile. We aren't sure if it is just some sort of backing, or an asphalt asbestos tile. They had already spent the weekend tearing most of it up and it is all over the place right now. any info/suggestions etc would be very greatly appreciated. - Jennifer 10/29/2012
Reply:
Asbestos-containing flooring in good condition does not have to be removed from a building, and worse, inept removal can create a much greater hazard than leaving most asbestos materials in place.
Asbestos was widely used as a filler in both asphalt-based and some vinyl based floor tiles of varying thicknesses, and extending to some thin, flexible self-adhesive backed tiles as well as some sheet flooring.
See ASBESTOS FLOOR TILE IDENTIFICATION PHOTOS 1949-1959 for an extensive photo guide to asbestos-containing flooring materials.
We recommend taking a look at the suggestions found
at ASBESTOS FLOORING HAZARD REDUCTION
Comment from reader: anonymous:
Hey Joe there's always a "risk" when removing anything that has to do with Asbestos. I understand that you probably didn't take caution at all with the removal and you probably weren't wearing the proper protection. There's two things that could be red flags.
1. I'd be worried if you were a constant to heavy smoker.
2. I'd also be worried if you've done this type of removal many times before or after without protection.
The only way to know for certain if true damage has been done is tell your Doctor or care provider about this incident and ask for their advice.
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