Carbone
Testa
Mossman
Miller
Editor's note: This is the second in a three-part series into the science of asbestos. The series will ask and attempt to answer what is myth, what is fact, what is not known and how the science affects the litigation of asbestos claims.
WASHINGTON (Legal Newsline) - There are some who say all forms of asbestos are unsafe and to be exposed to any amount is hazardous, while others say that one form of asbestos can be handled safely. Then there are some who are not sure.
Some of the leading scientific researchers, experts in the field of mesothelioma research and occupational medicine, have divergent opinions on the nature of the hazards caused by asbestos.
Four scientists were asked four questions about asbestos. Each one of them has distinguished themselves in some way in the field of asbestos science.
One of them was an American Cancer Society Research Scholar. One was the recipient of the Collegium Ramazzini's Irving Selikoff Award and recently made a discovery in the field. One is an official with the National Institute of Environmental Health Sciences. One received an award by the American Thoracic Society.
The questions asked of the researchers were:
None of the scientists interviewed currently participate in asbestos litigation for defendants or for plaintiffs.
The scientists interviewed are:
Here are their responses:
Is it true that there is no general consensus that chrysotile causes mesothelioma?
Prof. Carbone: There is unanimity that amphibole causes mesothelioma. There is no agreement that chrysotile causes mesothelioma.
Prof. Testa: Regarding chrysotile, there is much controversy about whether it causes mesothelioma. I am not sure the controversy is based on strong science. Based on my reading of the literature, there seems to be considerable evidence that chrysotile can cause mesothelioma based on epidemiological and rodent studies.
Prof. Mossman: Correct. The majority of scientists acknowledge that chrysotile is less pathogenic than crocidolite or amosite (amphibole) types of asbestos and must be inhaled at larger amounts to cause mesothelioma, as supported by lung fiber burden studies (see data by A. Churg and V. Roggli), but the difficulty is that we all have chrysotile (the most common type of asbestos) predominately in our lungs and the workers who have mesothelioma have been largely exposed to mixed types of asbestos fibers.
Dr Miller: I would say that is not true in terms of government and public health people from our standpoint at the National Institute of Environmental Health Sciences and the Center for Disease Control it is clear that it does.
Is it true that there is controversy that crocidolite is the most dangerous type of asbestos in terms of causing mesothelioma?
Prof. Carbone: Crocidolite is the most dangerous of the asbestos minerals in terms of causing mesothelioma.
Prof Testa: I don't think that there is much controversy that crocidolite is the, or at least one of the, most dangerous forms of asbestos in terms of causing mesothelioma. Crocidolite and other types of amphibole asbestos are thought to be more carcinogenic than chrysotile.
Prof. Mossman: No, I think the vast majority of scientists believe this is true
Dr. Miller: I would ask what is the most dangerous? We have seen more in those exposed to crocidolite. The animalsstudies indicate that crocidolite is the worse.
Is it true that much of the science has been influenced by the litigation? Have studies funded by companies been tendentious? Have studies been ideological?
Prof. Carbone: Some of the scientific literature has been influenced by the litigation. Read the acknowledgment section of many papers and see who financed the study, check whether the writer is a true scientist, someone with NCI or NIH or ACS or other credible peer-reviewed funding, whether the author has ever published anything important in a high impact journal (as defined by impact factor journal). (These are) all things easy to spot if you are in science but difficult to spot if you are not.
Prof. Testa: I think that it is likely that a small amount of science has been influenced by asbestos litigation. I have read that some studies funded by asbestos companies are biased, but I have no personal experience about this. As to whether some studies have been ideological, it is possible, given the enormous amount of money at stake, between product sales and asbestos litigation.
Prof. Mossman: Absolutely, this is why I have never participated as an expert witness in this arena. The legal community attends, advertises at, and supports a number of scientific meetings on asbestos. The Collegium Ramazinni meeting on the "Third Wave of Asbestos Diseases" held in NYC and organized by Philip Landrigan in the early 1990s... was supported by the plaintiff bar, labor unions and asbestos removal companies. It was questioned in a Science article.
Dr. Miller: Science which is funded by biased interests give biased results. We try to bring the best science to bear to find the effects of exposures. But clearly asbestos is one of those areas which has a lot of interest groups. Findings are questionable based on influences and biases.
Is it possible to reconstruct how someone who has mesothelioma was exposed to asbestos by working with brake shoes or some other occupationally related manner if the exposure occurred several decades earlier?
Prof. Carbone: If I ask you how many hours you spent working on a given task some 40-60 years ago, how accurate would your answer be? Now, imagine if you ask the question to the wife or friends of the subject because he is deceased. Imagine you ask my mom and my high school friends if when I grew up if I was exposed to asbestos, how accurate would the answer be? In short, these kinds of questions have some value when you look at a cohort, but individually? Well unless you are lucky to have good records, that almost never are available, then you are guessing.
Prof. Testa: With regard to your question about reconstructing how someone who has mesothelioma was exposed to asbestos occupationally several decades earlier, I would say the following: If a person were working occupationally with an amphibole fiber, and that type of fiber were persistent in the lung 40 years later, one could deduct that there was a causal connection. For chrysotile, the physical parameters of the fiber are such that they may not be found in the lung after several decades, but a carcinogen does not have to remain in the lung to cause mesothelioma. It could cause the initial genetic damage and disappear.
Prof. Mossman: No.
Dr. Miller: It is not difficult. We reconstruct exposure history all the time. This is how it is done for epidemiology studies.
After having read the answers of four distinguished scientists to four questions that are often at the center of asbestos litigation, one learns that there is near unanimity on some issues. But while there is unanimity on some things there are also divergent opinions on others - such as the gravity of the danger caused by chrysotile and if exposure history can be reconstructed.
While these are not scientists who work for or are funded by special interests groups, the same cannot be said uniformly about advocacy groups. Industry organizations that favor the use of asbestos, such as the Chrysotile Institute, will be criticized in the media as being biased.
The same type of scrutiny and the same standards could also be applied to those groups that oppose the use of asbestos.
For example, the website of the Asbestos Disease Awareness Organization - "the voice of the victims" - listed its 2011 conference sponsors. The list included, Shein Law Center, Simmons Attorneys at Law, the law firm of Belluck and Fox, the law firm of DeLuca and Nemeroff, and the Canadian Autoworkers Union.
But as the responses by the four scientists interviewed for this article indicate, even science has its controversies about asbestos.