Point of View

Stop using asbestos? Not so fast

November 12, 2009 

— Asbestos is the subject of what we may call reverse greenwash. Greenwash occurs when organizations claim that they are more environmentally friendly than they are. Reverse greenwash occurs when organizations try to scare people into thinking that environmental problems are more serious than they really are.

We can easily see this process with the efforts of law firms to criticize asbestos. Constant television ads promote lawsuits against companies that used asbestos, and some ads suggest that asbestos be banned from all further uses. I searched Google for "asbestos" and found that two of the top three sponsored links recommend filing lawsuits.

The problem with asbestos is that the term is used for two very different minerals. (The scaremongers don't mention this.) Almost all of the material called asbestos is the mineral chrysotile. Chrysotile ores consist of masses of tiny, soft, fibers that are very flexible. They are comparatively easy to mine and separate from surrounding rock.

The other mineral referred to as asbestos is different varieties of amphibole. These amphiboles occur as tiny needle-shaped crystals that break without bending. The broken needles are even sharper than the crystals in the original rock. Amphibole is difficult to mine and separate from its surrounding rock, and most of the amphibole used as asbestos comes from small areas within masses of chrysotile.

The main concern expressed about the use of asbestos is the development of mesothelioma, which the National Cancer Institute defines as "A rare type of cancer in which malignant cells are found in the lining of the chest or abdomen." Now the questions are whether inhalation of asbestos causes mesothelioma; if so, which kind of asbestos; and can asbestos be used safely.

These questions are important because asbestos is very useful. It is inflammable, a good electrical insulator and strengthens the matrix of such diverse products as cement and plastics, including floor tiles. Most asbestos is now used as a binder in cement.

With all of these good qualities, can asbestos continue to be used in our industries? Yes, if we are sensible.

First, we should realize that chrysotile by itself is not dangerous. An article in a 1988 issue of the medical journal Chest stated "although chrysotile asbestos can produce mesothelioma ..., the total number of such cases is small and the required doses extremely large." This observation is supported by the fact that no danger has ever been reported from chrysotile that occurs naturally in the environment. This comes about because chrysotile-bearing rocks decompose ("weather") easily and release chrysotile to be distributed by water and wind.

Obviously, it is important to use face masks to keep miners and mill workers from inhaling large quantities of chrysotile. That is no different from the protection required by miners against coal dust, lumber mill workers against sawdust or other mill workers against all types of dust.

Another reasonable precaution is to make sure that we mine chrysotile that does not contain amphibole. This can be done by thorough sampling of the ore body before mining. Geologists can easily distinguish chrysotile and amphibole with a microscope and point out areas where mines will produce only chrysotile.

Using chrysotile only in products such as cement and tiles adds another level of safety. The asbestos is safely locked into these materials and cannot be released during normal use.

The benefits and lack of hazards in using chrysotile show that we should continue to use asbestos in our industrial society. In particular, we shouldn't let reverse greenwashing frighten us away from it.

John J. W. Rogers is retired as the William R. Kenan Jr. professor of geology at UNC-Chapel Hill. He can be reached at jjwr@mac.com.

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