What is Asbestos?
What is Asbestos?
How Dangerous Is It and What Is It Doing In My House ?
These are all questions we’ve asked ourselves at one point or another. We’ve all wondered WHY would something potentially as carcinogenic would have been used with near-abandon for so long?
Why would this potential carcinogen be lurking our homes, our workplaces or even in the natural environment ?
Certified Asbestos Consultant (CAC)
I’m a California Certified Asbestos Consultant (CAC) and I’ve practiced in Oregon as an Asbestos Consultant there, too. I have worked for that state’s regulatory agency as a Permit Writer /Inspector and have had a prior career as a General Contractor. I have a minor in Chemistry and have an Emergency Medical Technician background as well. It helps to understand a little bit of human anatomy and physiology to understand why asbestos has been causing problems. I’ll explain this later.
“Asbestos” is the name given to a set of six commercially used natural geologic (from rocks) silicate fibers that all have similar physical qualities of heat, fire, acid and caustic resistance. There are two general types of asbestos fibers we will generally see referred to industry and construction ; “Serpentine” and “Amphibole”. The difference at this point is that one type of these fibers, of which there is only one member (Chrysotile) makes up about 95% of the asbestos that was used in this country. Chrysotile has an affinity for water, yet will not dissolve. This is due to a characteristic of the asbestos fiber itself: it is actually a rolled-up sheet of molecules…….creating a hollow tube….which absorbs water without distorting the fiber’s shape. Asbestos and cellulose (wood) fibers (that make paper) blend and mix very well.
Asbestos in the home
Wallpaper manufactures used Chrysotile in the “paper” backing of wallpaper, which comes into contact with moisture present in the wallpaper paste until that paste is dry.
The other types of asbestos are called the “amphiboles”” and they are hydrophobic; they repel water. This is especially useful for fluid filters and water cooler/heat exchangers. Other members of this group are called “Naturally Occurring Asbestos” which can be found in the natural environment. In the soil or in the rocks beneath your feet. In fact, the California state rock is “Serpentine”. It’s a green to blue shaded bedrock that will have an occasional white or light gray “vein” running through it. This is where we’ll find a type of asbestos. It’s not the same exact type that is used in construction or in industry, but is still a “amphibole asbestos” that is found in ultramaphic rock formations.
In California, ultramaﬁc rock, including serpentine rock, is found in the Sierra foothills, the Klamath Mountains, and the coast ranges. This type of rock is present in at least 44 of California’s 58 counties. Not all ultramaﬁc rock contains asbestos; it only has the potential to contain asbestos. Environmental testing can determine if a rock contains asbestos ( credit to CDC).
“Ultramaphic rock” are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are composed of usually greater than 90% mafic minerals (dark colored, high magnesium and iron content). The Earth’s mantle is composed of ultramafic rocks. Ultrabasic is a more inclusive term that includes igneous rocks with low silica content that may not be extremely enriched in Fe and Mg, such as carbonatites and ultrapotassic igneous rocks. (credit to Wikipedia).
While we can clearly see the fibrous nature of asbestos, and can also see the flexibility of Chrysotile fibers in the un-processed form, we can not see all the fibers that are in building materials or other industrial equipment. Asbestos was ground down, or “milled” to suit the requirement of the manufacturer or the intended purpose of the asbestos fibers. For instance, in “nine by nine” Vinyl Floor Tile ( and some 12” by 12” VFT, too), the asbestos fiber content was generally there to “fill” in for the more expensive vinyl beads used to manufacture the material. The asbestos fibers found in VFT are about 1 micron thick. A human hair can range up to 40 microns thick.
Another physical property was resistance to thermal expansion or contraction. Because vinyl products, as we know, can “stretch” when they get hot, and “shrink”
when they get cold. It’s easy to see where vinyl tile that did not have the stabilizing affect of a mineral/rock might easily “stretch “ and pop off of the floor and away from the mastic. It would be difficult to find a vinyl floor tile today with asbestos in it. This is not to say that asbestos is “illegal”. In fact, some countries have banned it’s use, the United States will allow some manufactured products to have asbestos, but such must be clearly labeled, and is heavily regulated in manufacturing processes. Simply to put; if asbestos can not be replaced with a material that is as good, then it is possible for asbestos to be used in that product and that product may be imported into this country today. It is more of the exception now, than the rule.
As a CAC, I am always ready to explain the complicated set of regulations that surround this material. I welcome the opportunity to discuss the multiple regulatory agencies that have some role in asbestos regulations ( erg. EPA, Cal-EPA, OSHA, Cal-DOSH, NIOSH, MSHA,Local Air Quality Management Districts, and Fire Departments and others depending on your location). It’s important to know which set of regulations have the most bearing on any given situation, in fact, it’s critical. There are area regulations dealing with disposal of asbestos containing materials and there are even more restrictive regulations that protect people that work around asbestos containing building materials.
I also look forward to putting the laboratory results from my sampling investigations into perspective and in context for my clients. I am especially keen that they understand “relative risk” of a material, and that not all asbestos containing materials are as ‘risky’ as another. Here’s an example. Let’s say you have a 1965-built home. You have a ceiling treatment that meant to hold-down or eliminate echoes in the house. This is what “acoustical ceiling” treatment was meant to do. Another word for this material is “popcorn”. I think it looks more like cottage cheese. The point is, that this material had to be sprayed on and to improve that process, asbestos was placed into the “hopper” ( a tool used to do the application process) when the tip of the air spray began to plug-up. Asbestos would be added by the handful into that hopper. Further, the aggregate of this treatment has been sometimes been vermiculite..another mined product, found alongside and processed on the same equipment as tremolite asbestos. Chrysotile asbestos was also added to it to improve fire resistance. ( the distribution as asbestos in popcorn ceiling is usually not uniform..different concentrations will exist). I usually see figures of 5% to 15% asbestos in “pre-1985” popcorn ceilings. Are they dangerous? Only if “man-handled” and scraped off the wrong way. If proper precautions are not followed, if clean-up is not performed properly..then, yes, it can be. If left alone and kept in good repair…which includes preventing water damage to that sheet rock ceiling that this material is applied to, if kept in good condition, then, no..not really. The EPA suggests just as much. If you’re going to remove popcorn ceiling from your home, please consider hiring a professional abatement company to perform this; there’s more involved than meets the eye. On the other hand, if you are a rental owner, or if you own more than 5 dwellings—apartment units or single family homes, then you are required to survey your property for asbestos BEFORE any renovation or any demolition work, and, you have to hire professionals to do the work on your rental properties. A homeowner can still perform work on their own homes. Everybody has to notify their project with the local Air Quality Maintenance District, regardless the size of their project..and they have to get a permit if their project is greater than 100 square feet in size. This has to be done ten days before the project starts, or they can pay for an emergency permit and pay an expedited fee.
Everybody is always required to dispose of asbestos containing materials (> than 1%) in specific ways, and anybody working with asbestos containing materials of greater than one-tenth of one percent (1/10th of 1%) is required to have asbestos training…( with very few exceptions).
How Dangerous IS Asbestos ?
The first thing that I want to say is that there is “no known safe level of exposure to asbestos”. This is the official position of the Environmental Protection Agency. This is mirrored by all other regulatory agencies. However..and this is where I can start to lose people…however, there is such a thing as “permissible exposure limits”. This is a number of asbestos fibers (ff) per cubic centimeter of air (cc) averaged over an 8 hour period of time. This is a “time-weighted average” or “TWA” This number has been dropping since this term’s inception. It is currently 0.1 fiber per cc of air, over 8 hours. There is also an “excursion limit” of 1.0 fiber per cc per 30 minutes of exposure. These numbers and regulations are applied to abatement workers and are measured by taking air samples while they work. There are formulas used that factor-in the efficiency of the mask system for TWA measurement and there are no filters used for “excursion limits” calculations. It’s all about relative risk.
Asbestos and the disease processes associated with exposure (primarily inhalation) are primarily a function of exposure over time. It’s time-dose weighted. You can have a large dose/exposure only once and can develop disease processes , or you can have very small doses over an extended period of time and develop lung cancer, asbestosis, pleural plaques or mesothelioma. Or, you can do both and not get sick at all. How can that be? There is a biological, physiological component to disease progression.
There’s at least two things going on here in the development of disease: 1) inhalation of “sharp fibers”. These fibers, which do not specifically have to be asbestos…but have to be small enough to puncture a cell, accumulate in the lungs. They eventually travel their way through the lung tissue and rest against the outer lining of the chest cavity. They can cause cancer along the way, but they cause cancer called “mesothelioma” at the lining of the chest cavity. It is here, that after ten to thirty years of the body trying to dissolve and get rid of the foreign objects, that cancer is started. Our own bodies will release substances that will dissolve most organic foreign bodies. Except for asbestos. Remember, one it’s primary qualities is that it is chemically resistant. Our cells actually produce what amounts to hydrogen peroxide, and use that to attempt to break-down the foreign objects. After three decades or after one, the resultant damage can alter the DNA of surrounding cells and can start cancerous growth. There is no cure for this type of cancer, and the average life expectancy after initial diagnosis is 6 months.
Smoking while working with asbestos raises the risk of cancer more than exponentially…more than ten-fold.
Does everybody who works with asbestos or who works with asbestos and smokes..get cancer? No. Why? Genetics and other factors we simply don’t fully understand yet, all play a role in disease response. So why all the fuss? In as short an answer as I have ever mustered for this question: “kids”. Remember, it takes a certain amount of time to develop disease from asbestos exposure. Our schools in this country basically range from the Baby Boomer era, which also happens to be when asbestos was used most widely used, and these buildings are in various states of repair. These older buildings are potential sources of contamination or exposure. The occupants of these buildings, especially students and staff, spend time in contact with asbestos containing building materials every day. From polishing vinyl asbestos floor tile to working on TSI covered boilers, there are ample opportunities for asbestos exposure every day at most older schools. Our government finally recognized this fact in the mid seventies. We finally began requiring Asbestos Surveys and the creation of Management Plans in our schools. This came about because of “AHERA” or, Asbestos Hazard Emergency Reduction Act which was signed into law in 1986 ( 40 CFR 763). In 1992, ASHARA ( Asbestos School Hazard Abatement Re-authorization Act) was passed and extended AHERA regulations to public and commercial buildings. AHERA makes your school district acknowledge whether or not it has asbestos containing materials, or at least suspected asbestos containing materials, and it requires regular and routine assessment of these materials. Each school is to maintain a set of books on-site—it has to be on-site—that list a “management plan” for asbestos if there is any on campus. This book is to list the locations of suspect or known asbestos containing building materials, or even “presumed” asbestos containing materials -”PACM”. Each school is to have an initial Asbestos Survey performed by the summer of 1991, and, a periodic surveillance inspection of the identified materials or systems every 6 months. AHERA also gave us the detailed training requirements needed for persons to perform various levels of responses to asbestos. This includes a mandatory 2-hour Asbestos Awareness course for all Custodial staff or those who’s work will have them come into contact with ACM on a regular basis. It also lists the requirements for establishing safe and contained work zones to remove asbestos safely. Many other agency regulations are AHERA-based.
It needs to be mentioned that asbestos doesn’t always “stay” where it was put. Asbestos has been shown to come home on the clothes and tools of workers, who in turn expose their families to this known carcinogen through routes as innocuous as doing the laundry. Spouses of workers have contracted mesothelioma from their husbands work clothes. Therefore, it could be said, if we limit the exposure to asbestos of one person , especially in a working environment, we thereby can reduce the exposure of other persons by extension.
We also need to mention the fact that asbestos has performed remarkably well for many applications for which there are no substitutes; from fire resistant clothing ( not containing bi-phenols) to the war effort of WWII, where boiler insulation was a critical use of asbestos. Asbestos fibers perform extremely well in brake and clutch discs. Automotive mechanics have also been exposed to asbestos and are now cautioned to never use compressed air to clean off brake assemblies ( to avoid creating a hazardous dust and then dispersing it).
Okay, now why is this stuff in my home?
Short answer: asbestos tended to improve the function or application of, or service life of almost anything you could add it to. Please note that asbestos is not in all houses. House built before 1986 have a much greater chance of having been built with at least one or two asbestos containing building materials. My own field experience, in both construction and in environmental regulation, has shown a “J” curve in terms of distribution of asbestos materials, in houses and buildings, over time. It very clearly shows that the majority of asbestos was used during the late 60s to late 70’s. There was asbestos used in building since the the the turn of the 20th Century which then steadily grew to about the mid 70’s. After then, usage began to taper off dramatically. Before then, usage ramped up steadily.
Asbestos also imparted strength and weather resistance, it prevented cracks in stucco and sheet-rock topping, it made wallpaper easier to hang and it was inert. Asbestos helped hold in heat or hold out cold, it was cheap, plentiful and very easily mined. It prevented fires from spreading. It was used by our grandmothers to keep her iron from scorching her ironing board. It was used as a filter element in the food and beverage industry. It was used in water and sewer pipes. Ingestion by mouth is another means by which to become exposed to asbestos, where cancer of the alimentary system can happen. However, the primary disease process is caused by inhalation. Asbestos was used in paints, in lighting and electrical fixtures and in insulation on wires. It was used in roofing and in roof felts as well as asphaltic shingles. It was used in gaskets and felts. It was used in firebox lining of furnaces. It was cast into molds with phenolic resins and early plastics in order to prevent “warping” of the item when it cooled. It helped mastics and glues to hold, not crack, yet make them just pliable enough to be workable.
During the Post War Building Boom, there were ample opportunities to discover more uses for this group of mineral fibers. We had stockpiles of this material on hand and it was cheap and very plentiful. There eventually became more than 3,000 different products that contained asbestos…from movie theater screens to early molded plastics. Did you know that “fake snow” was asbestos? How about the flocking on Christmas Trees ? ( there was a reason that flocking was fire resistive—it had asbestos in it). Due to lack of record keeping and proprietary secrets, no complete record of these materials or objects exists. We find new ACM everyday.
Despite the fact that we “discover” new asbestos containing building materials or other manufactured products from pre 1987 that contain asbestos, the associated health effects were under scrutiny for much longer than that. We knew that there was a disease associated with working with asbestos, well before WWI or WWII.
I’ll discuss that more in my next blog
Geoff P McPherson, CAC # 13-5111
Who is Healthy Building Science?
Environmental Testing Services at HBS
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