Tag: asbestos

Vermiculite


Image by/from WikiMedia Commons

Vermiculite, a hydrous phyllosilicate mineral, undergoes significant expansion when heated. Exfoliation occurs when the mineral is heated sufficiently, and commercial furnaces can routinely produce this effect. Vermiculite forms by the weathering or hydrothermal alteration of biotite or phlogopite.
Large commercial vermiculite mines currently exist in Russia, South Africa, China, and Brazil.

Vermiculite was first described in 1824 for an occurrence in Millbury, Massachusetts. Its name is from Latin vermiculare, to breed worms, for the manner in which it exfoliates when heated.

It typically occurs as an alteration product at the contact between felsic and mafic or ultramafic rocks such as pyroxenites and dunites. It also occurs in carbonatites and metamorphosed magnesium-rich limestone. Associated mineral phases include: corundum, apatite, serpentine, and talc. It occurs interlayered with chlorite, biotite and phlogopite.

Vermiculite is a 2:1 clay, meaning it has two tetrahedral sheets for every one octahedral sheet. It is a limited-expansion clay with a medium shrink-swell capacity. Vermiculite has a high cation-exchange capacity (CEC) at 100-150 meq/100 g. Vermiculite clays are weathered micas in which the potassium ions between the molecular sheets are replaced by magnesium and iron ions.

In 2014, South Africa, Brazil, the US, and China were the top producers of mined, concentrated and unexfoliated vermiculite, with about 90% world share. South Africa’s production is decreasing, while Brazil’s is significantly increasing.

While some end processors and exfoliators of vermiculite specialize, with proprietary products sold in a wide variety of industries, some have more varied end products, with less stringent technical requirements. Some vermiculite exfoliators blend with lower-cost perlite also. Vermiculite exfoliators have an international trade association called The Vermiculite Association to represent the industry’s interests and to exchange information.

Today spray-applied fireproofing materials use vermiculite, other industrial minerals, and expanded polystyrene, depending upon the exact commercial product. The ingredients for these products all have to meet stringent regulatory requirements, particularly in the US and Europe. In the past, vermiculite from the W. R. Grace mines in Montana, have been associated with asbestos. Therefore, old spray-applied fireproofing, pre-1991, may contain small quantities of asbestos. In August 2014, the NYSDoH qualified two, more exact, test methods, better designed to identify materials with this potential problem, and assist in safely dealing with any issues associated with its removal. Modern spray applied fireproofing today is made with vermiculite that does not contain asbestos and is carefully monitored at all stages of mining and production to ensure this is the case.

Although not all vermiculite contains asbestos, some products were made with vermiculite that contained asbestos until the early 1990s. Vermiculite mines throughout the world are now regularly tested for it and are supposed to sell products that contain no asbestos. The former vermiculite mine in Libby, Montana, did have tremolite asbestos as well as winchite and richterite (both fibrous amphiboles)—in fact, it was formed underground through essentially the same geologic processes as the contaminants.

Pure vermiculite does not contain asbestos and is non-toxic. Impure vermiculite may contain, apart from asbestos, also minor diopside or remnants of the precursor minerals biotite or phlogopite.

The largest and oldest vermiculite mine in the United States was started in the 1920s, at Libby, Montana, and the vermiculite was sold under the commercial name Zonolite. The Zonolite brand and the mine were acquired by the W. R. Grace and Company in 1963. Mining operations at the Libby site stopped in 1990 in response to asbestos contamination. While in operation, the Libby mine may have produced 80% of the world’s supply of vermiculite.

The United States government estimates that vermiculite was used in more than 35 million homes, but does not recommend its removal. Nevertheless, homes or structures containing vermiculite or vermiculite insulation dating from before the mid-1990s—and especially those known to contain the “Zonolite” brand—may contain asbestos, and therefore may be a health concern.

An article published in The Salt Lake Tribune on December 3, 2006, reported that vermiculite and Zonolite had been found to contain asbestos, which had led to cancers such as those found in asbestos-related cases. The article stated that there had been a cover-up by W. R. Grace and Company and others regarding the health risks associated with vermiculite and that several sites in the Salt Lake Valley had been remediated by the EPA when they were shown to be contaminated with asbestos. W. R. Grace and Company has vigorously denied these charges.

The vermiculite deposit at the mine in Libby, Montana, was (and is) heavily contaminated with asbestos. Numerous people were knowingly exposed to the harmful dust of vermiculite that contained asbestos. Unfortunately, the mine had been operating since the 1920s, and environmental and industrial controls were virtually non-existent until the mine was purchased by the W. R. Grace and Company in 1963. Yet, knowing the human health risks, the mining company still continued to operate there until 1990. Consequently, many of the former miners and residents of Libby have been affected and continue to suffer health problems. Over 400 people in the town have died from asbestos-related disease due to contamination from vermiculite mining from nearby Zonolite Mountain, where soil samples were found to be loaded with fibrous tremolite (known to be a very hazardous form of asbestos), and countless others there who insulated their homes with Zonolite have succumbed to asbestos-related diseases, most of whom never were employed in environments where asbestos was an issue.

After a 1999 Seattle Post-Intelligencer story claimed that asbestos-related disease was common in the town, the EPA, in response to political pressure, made cleanup of the site a priority and called Libby the worst case of community-wide exposure to a toxic substance in U.S. history. The EPA has spent $120 million in Superfund money on cleanup. In October 2006, W. R. Grace and Company tried to appeal the fines ($54.5 million) levied on them from the EPA, but the Supreme Court rejected the appeal. The United States government is also pursuing criminal charges against several former executives and managers of the mine for allegedly disregarding and covering up health risks to employees. They are also accused of obstructing the government’s cleanup efforts and wire fraud. To date, according to the indictment, approximately 1,200 residents of the Libby area have been identified as suffering from some kind of asbestos-related abnormality. Jury selection was to have been completed in February 2009. The case ended in acquittals on May 8, 2009. On June 17, 2009, the EPA issued a public health emergency in and near Libby, thereby allowing federal agencies to provide funding for health care, and for removal of contaminated insulation from affected homes.

Curated with thanks from Wikipedia.

Transite


Image by/from Mewtu

Transite originated as a brand that Johns Manville, an American company, created in 1929 for a line of asbestos-cement products, including boards and pipes. In time it became a generic term for other companies’ similar asbestos-cement products, and later an even more generic term for a hard, fireproof composite material, fibre cement boards, typically used in wall construction. It can also be found in insulation, siding, roof gutters, and cement wallboard. The more prevalent transite found in wall construction and roofing tiles for example, will last anywhere from 50 years to over 100 years.

The use of asbestos, a proven carcinogen, to manufacture transite was phased out in the 1980s. It was replaced by crystalline silica, which the International Agency for Research on Cancer has classified as being carcinogenic to humans (Class 1). Crystalline silica is also known to cause silicosis, a non-cancerous lung disease.

Originally, transite had between 12-50% of asbestos fiber added to a cement base to provide tensile strength (similar to the rebar in reinforced concrete), and other materials. It was frequently used for such purposes as furnace flues, roof shingles, siding, soffit and fascia panels, and wallboard for areas where fire retardancy is particularly important. It was also used in walk-in coolers made in large supermarkets in the 1960s, 1970s and even the 1980s. Other uses included roof drain piping, water piping, sanitary sewer drain piping, laboratory fume hood panels, ceiling tiles, landscape edging, and HVAC ducts. Because cutting, breaking, and machining asbestos-containing transite releases carcinogenic asbestos fibers into the air, its use has fallen out of favor. Despite asbestos-containing transite being phased out, it is still not banned in the United States; some 230,000 deaths have been attributed to it. Demolition of older buildings containing transite materials, particularly siding made from transite, requires special precautions and disposal techniques to protect workers and the public.

The transite that is produced today is made without asbestos. Transite HT and Transite 1000 are currently available fiber cement boards that contain crystalline silica, which the International Agency for Research on Cancer has classified as being carcinogenic to humans (Class 1). Crystalline silica is also known to cause silicosis, a non-cancerous lung disease.

Curated with thanks from Wikipedia

Tremolite


Image by/from Didier Descouens

Tremolite is a member of the amphibole group of silicate minerals with composition: Ca2(Mg5.0-4.5Fe2+0.0-0.5)Si8O22(OH)2. Tremolite forms by metamorphism of sediments rich in dolomite and quartz. Tremolite forms a series with actinolite and ferro-actinolite. Pure magnesium tremolite is creamy white, but the color grades to dark green with increasing iron content. It has a hardness on Mohs scale of 5 to 6. Nephrite, one of the two minerals of the gemstone jade, is a green variety of tremolite.

The fibrous form of tremolite is one of the six recognised types of asbestos. This material is toxic, and inhaling the fibers can lead to asbestosis, lung cancer and both pleural and peritoneal mesothelioma. Fibrous tremolite is sometimes found as a contaminant in vermiculite, chrysotile (itself a type of asbestos) and talc.

Tremolite is an indicator of metamorphic grade since at high temperatures it converts to diopside.

Tremolite occurs as a result of contact metamorphism of calcium and magnesium rich siliceous sedimentary rocks and in greenschist facies metamorphic rocks derived from ultramafic or magnesium carbonate bearing rocks. Associated minerals include calcite, dolomite, grossular, wollastonite, talc, diopside, forsterite, cummingtonite, riebeckite and winchite.

Tremolite was first described in 1789 for an occurrence in Campolungo, Piumogna Valley, Leventina, Ticino (Tessin), Switzerland.

One of the six recognized types of asbestos. Approximately 40,200 tons of tremolite asbestos is mined annually in India. It is otherwise found as a contaminant.

Curated with thanks from Wikipedia

Why the Deadly Asbestos Industry is Still Alive and Well

Deadly Asbestos

This video covers Russia and the USA and shows that the dangers of asbestos are not being taken seriously, or if they are, still very little is being done about them at a top level.

Why might this be? Well, one of the major sayings when it is difficult to find an answer to something happening that seems nonsensical is to “Follow The Money”. That means that you should look at the situation to see whether someone could  be making money from things staying as they are. (It follows on from the French saying, “Cherchez la femme”, which means to look for the woman behind what a man is doing!) You may also know the saying as “Money Talks”, that is, if money is available for doing or not doing something, it is likely that it will or will not be done, no matter how serious or nonsensical the situation.

Where might the money be in relation to asbestos?

  1. There is nothing as good and cheap as asbestos when it comes to fireproofing and insulating. Manufacturers still want to use it. If they cannot use it in developed countries, they will use in less developed countries.
  2. The countries or companies that own the deposits of asbestos want to make money from them.
  3. There are large deposits of asbestos available and the mines that extract it provide jobs and incomes in some remote areas, where no other jobs are available.

The Real Story of Asbestos

How Did We Find Out About Asbestos

How long have we known it’s dangerous to health?

This short video provides the answers.

Why Are Popcorn Ceilings So Terrible

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Popcorn Ceilings May Contain Asbestos

Many older houses have what are known as popcorn ceilings. If you are thinking of buying one of these older houses, then find out about these types of spray on ceiling covers before making an offer, so you know whether you are willing to live with it or able to afford the cost of removing it.

What Is A Popcorn Ceiling

A popcorn ceiling is the name given to ceilings that have been treated with a spray-on textured paint. They are also known as acoustic ceilings, because they have sound-proofing qualities. Many people do not like them, firstly because they are old fashioned and not what they consider to be in tune with modern decor and secondly because they may contain asbestos.

Does It Contain Asbestos?

Volunteers Exposed To Asbestos Dust

 

 

 

 

 

 

 

 

 

 

This case dates back to the year 2009 in Michigan, USA when a group of volunteers and untrained employees were tasked by Detroit International Bridge Co, with cleaning up an old building at Michigan Central Station. The company was subsequently fined by the OSHA for exposing these people to asbestos dust and other toxic materials.

Damages Award £250,000 for Secondary Exposure To Asbestos

The family of a woman who died of mesothelioma has been awarded over $320,000 compensation against the firm who employed her husband in their boiler making factory.

She was exposed to the dust on her husband’s overalls when she shook them out prior to washing  them every evening. This is termed secondary exposure and this case is the first in Scotland, UK to have been awarded such damages. The firm was called Babcock & Wilcox, now Babcock International. You can read the full story here. There is another article about fines for contravening asbestos regulations here.

So Useful So Dangerous

Asbestos is an extremely useful material, unfortunately, it is also extremely dangerous. As a non flammable insulator, it was used in fire curtains, home insulation, as ironing stands, for automobile brakes, in ceiling decoration, house sidings and so many more places. It was also used in cigarette filters! Both government and private industry promoted the use of asbestos, even though they may already have known at the time that it was dangerous and caused cancer. Below is one of the promotional films made many years ago before the dangers of asbestos were publicly known.

Sources Of Asbestos in Homes

Where To Find Asbestos In The Home

It’s often surprising just where exactly asbestos can be found in older homes and what needs to be done to ensure a safe asbestos clean up. The best route is to bring in the experts. Qualified asbestos removal firms will have trained staff, who will know where exactly to look for possible uses, such as sidings, floor tiles,  asbestos duct or ductwork insulation and boiler areas for instance. They will also be trained to use the correct methods, such as taping off areas with asbestos danger tape, using asbestos cleaning cloths and disposal bags or they may possibly recommend asbestos encapsulation methods for areas where the material does not need removal and is not friable but where work is needed to ensure any asbestos cannot be accidentally released.

The Health and Safety Executive in the UK has produced an image that shows some (not all) of the possible places to find asbestos in the home. The numbering guide can be found on their page. The picture is linked to the page it comes from.

www.asbestosremovalz.com

 

 

 

 

 

 

 

There is an old film available that shows many of the areas where asbestos can be found in an older house. Warning: the video is actually called “how to  safely remove asbestos” but what it really does is show you where asbestos is located. If you are interested in watching to see how many ways asbestos was used in older houses, then check out the asbestos documentary below.

 

This page contains public sector information published by the Health and Safety Executive and licensed under the Open Government Licence