Selikoff and the Mystery of the Disappearing Amphiboles

The goodfellas of occupational medicine are fond of telling stories about industry suppression of studies, but they don’t much like to hear or tell similar stories about how iconic public health scientists did the same.  When Sir Richard Doll died, the goodfellas attacked his consultations with industry; when Dr. Irving Selikoff died, they lauded his work.  When it comes to an iconic figure such as Dr. Irving Selikoff, the goodfellas are especially intent upon preserving his reputation at all costs.

When the biography of Irving Selikoff is written, however, the author will have to deal with Selikoff’s suppression of science on the health effects of asbestos! 

One of Selikoff’s agenda items was to treat all asbestos minerals the same, even though the scientific world differentiates between and among the different minerals that make up the class of minerals known as “asbestos.”  That class includes chrysotile (white asbestos, a fibrous serpentine mineral), crocidolite (blue asbestos, a fibrous form of riebeckite), amosite (brown asbestos, named for “asbestos mines of South Africa, a fibrous form of cummingtonite-grunerite), anthophyllite (only the fibrous form), tremolite (only the fibrous form), and actinolite (again only the fibrous form).  All the asbestos minerals are silicates, as are most of the minerals on planet Earth.  Chrysotile is in the serpentine family of silicates; whereas the other asbestos minerals are all amphiboles.  Each of these asbestos minerals has different physico-chemical properties.  All are recognized to cause asbestosis, and to the extent that they have caused asbestosis, lung cancer as well.  The asbestos minerals, however, have very different capabilities as far as mesothelioma is concerned.

Selikoff was intent upon treating all the asbestos fiber types the same, even though the scientific community has long recognized that the fiber types are very different with respect to mesothelioma causation.

By way of example, in a cohort of British workers who assembled gas masks during World War II, close to 9% of all deaths were due to mesothelioma. See J. C. McDonald, J. M. Harris, and G. Berry, “Sixty years on: the price of assembling military gas masks in 1940,” 63 Occupational & Envt’l Med. 852 (2006).  Workers who had even longer exposures to crocidolite experienced even higher mesothelioma rates.  In an American factory that used crocidolite to make filters and filter papers, including filters for cigarettes, mesothelioma made up close to 18% of all deaths.  James A. Talcott, et al., “Asbestos-associated Diseases in a Cohort of Cigarette-Filter Workers,” 321 N.Engl.J.Med. 1220 (1989).

In chrysotile only populations, the prevalence of mesothelioma as a cause of death is very low (well under 1%) and it may well be non-existent. 

Selikoff, however, was intent upon having all fiber types treated the same, both in regulation, and in litigation.  Selikoff was an amphibole denier, or at least a crocidolite denier, in the same vein as the so-called Global-Warming Deniers, who are so ridiculed these days.

Let’s start with a quote from a 1990 paper by Dr. Selikoff:

“Insulation workers in the United States and Canada were exposed to materials that contained chrysotile asbestos in early years and chrysotile plus amosite, later. The chrysotile used, from Canada, is believed to have contained small proportions of tremolite, as a contaminant, generally less than 1%. The extraordinary cancer risk demonstrated among insulation workers would therefore refer only to the fibrous materials to which they were exposed, and to the conditions of such exposure. We have no information on the effects of crocidolite in similar circumstances nor whether reduction of exposure would result in decreased risk.”

Herbert Seidman & Irving Selikoff, “Decline in Death Rates among Asbestos Insulation Workers l967-1986 Associated with Diminution of Work Exposure to Asbestos,” 609 Annals N.Y. Acad. Sci. 300, 311 (1990)

Now there are two remarkable misstatements in this passage, and they are so clearly wrong that a disinterested reader may well wonder about the motivations that gave rise to the falsehoods.

First, the suggestion that amosite exposure came about “later” in the exposure of insulators is factually wrong.  The United States Navy, and its private contractor shipyards, had a seemingly endless appetite for amosite, in the form of blankets, and later in the form of pre-molded pipecovering insulation (such as Unibestos).  The Navy’s own documents show that amosite featured heavily in the most injurious exposures that shipyard workers experienced before and during World War II.  Selikoff had written about the existence of asbestos-related disease in American shipyards.  See, e.g., Selikoff, Lilis, and Nicholson, “Asbestos Disease in United States Shipyards,” 330 Annals N.Y. Acad. Sci. 295 (1979); Irving J. Selikoff & Cuyler Hammond, “Asbestos-associated Disease in United States Shipyards,” 28 CA – A Cancer Journal for Clinicians 87 (1978).  His ignorance on this point is hard to square with the depth of his knowledge about shipyard exposure circumstances.

Second, and even more remarkable, is the suggestion that the insulators under study had no exposure to crocidolite (blue) asbestos.  This misrepresentation seems neither innocent nor immaterial.

Selikoff, himself, can be shown to have known both suggestions, about amosite’s late arrival, and the non-use of crocidolite, were false.  In a paper published in 1965, Selikoff reports on the content of asbestos insulating materials:

“In later specimens so obtained, crocidolite has also been found. Moreover, materials used for ship insulation, while containing the same amounts of asbestos as above, began in 1934 to have significant amounts of amosite in addition to chrysotile, because of the lighter weight of the material.”

I. J. Selikoff, J. Churg, E. C. Hammond, “The Occurrence of Asbestosis among Insulation Workers in the United States,” 132 Annals N.Y. Acad. Sci. 139, 142 (1965).  So Selikoff was well aware of the use of amosite, going back to the 1930s, and he was well aware of the use of crocidolite in the United States.

Selikoff had other sources of the knowledge of where, and how much, amphibole asbestos was used in the United States.  During the course of discovery in the Caterinnichio case, I obtained a manuscript of a study that Selikoff and his colleagues prepared, but never published.  The study examined the mortality, and especially the cancer mortality, of workers at a Johns-Manville asbestos product manufacturing plant in New Jersey.  William J. Nicholson, Ph.D. & Irving J. Selikoff, M.D., “Mortality experience of asbestos factory workers; effect of differing intensities of asbestos exposure”: unpublished manuscript produced in litigation (circa 1988).  Selikoff’s failure to publish this paper is curious given his tireless and repeated republication of data from his insulator cohort.  Selikoff’s failure to publish this paper, however, is more concerning because the paper acknowledges the undeniable — Johns Manville used crocidolite asbestos in its products:

“[O]ther asbestos varieties (amosite, crocidolite, anthophyllite) were also used for some products. In general, chrysotile was used for textiles, roofing materials, asbestos cements, brake and friction products, fillers for plastics, etc.; chrysotile with or without amosite for insulation materials; chrysotile and crocidolite for a variety of asbestos cement products.”

Id.  Interestingly, the failure to publish research is a claim that is often made against industry generally.  The suppression of studies clearly takes place outside the world of commercial interests.

Johns-Manville was hardly alone in its commercial use of crocidolite.  Back in July 1962, Selikoff visited the Asbestos Corporation of America, and memorialized his observations in a memorandum.  The general manager of the company, Wade I. Duym, appeared to have hosted the visit.  Here are some quotes from Selikoff’s 1962 memorandum:

“Amosite.  This continues to be used in the insulation trade primarily; for example, it is the asbestos of choice for high temperature insulation cement inasmuch as it has less water in combination.  Similarly, it is used in the calcium silicate insulation products (“magnesia”) [sic].”

Id. at 1.

“Other insulation uses [of amosite] include spray insulation.”

Id. at 2.

“The amosite used comes only from Africa.  The two large companies involved in its exploitation are the Cape Asbestos Company and Turner & Newell.  Representatives in the U.S. are the North American Asbestos Corporation.” 

Id. at 2.

“Crocidolite.  This is relatively inexpensive (10 – 12¢) and it is also exceedingly strong and is therefore used in asbestos cement products, especially since it is fairly resistant chemically.  Its sources are primarily Africa and Bolivia and samples of both were made available to us.”

Id. at 5.

“Of historical note, and of some peripheral interest, is the fact that Kent cigarettes for years used filters made of blue asbestos.  It would have been interesting to examine the smoke inhaled through such filters for particles of asbestos.  Bolivian blue asbestos was utilized.” 

Id. at 6.

At the 1964 meeting of the New York Academy of Sciences, which Selikoff organized, and the proceedings of which he edited, several investigators reported the content of asbestos insulation.  Hendry, a Johns-Manville geologist, noted that for the year 1963, the United States used 22,000 tons of amosite in its manufactured products. For the same year, 17,000 tons crocidolite were used, in acid-resistent filters, packings, insulations, and certain types of lagging. N.W. Hendry, “The Geology, Occurrences, and Major Uses of Asbestos 132 Annals N.Y. Acad. Sci. 12, 19 (1965). 

At this meeting, Harrington reported  on the asbestos content of insulation pipe sections.  He found chrysotile and crocidolite asbestos in equal proportions in specimens of 85% magnesia pipe-covering sections. Harrington, “Chemical Studies of Asbestos,” 132 Annals N.Y. Acad. Sci. 31, 41 (1965). 

This contemporaneous evidence is hardly surprising or novel.  The United States Department of Commerce keeps statistics, on importation of various kinds of asbestos.  For several years, crocidolite imports exceeded amosite, and often both minerals were imported in similar quantities.

Selikoff’s distortions have become “evidence” that fuels the asbestos litigation industry.  Here is a typical example of how plaintiffs’ counsel, Baron & Budd, exploit the misrepresentations:

“Published epidemiological studies demonstrate significantly increased rates of mesothelioma, often more than double what was expected, in chrysotile-exposed populations.[32] The cohort of more than 17,000 insulators studied by Dr. Selikoff and Dr. Frank worked primarily with chrysotile and developed mesothelioma at a significantly higher rate than the general population.[33] Dr. Selikoff explained that the increase in mesothelioma and other asbestos-related diseases ‘cannot be ascribed to other than the one asbestos fiber that was in regular use in insulation materials during the 1930s – chrysotile’. [34] As Dr. Frank reiterated, it was hard to imagine that . . . a few percent of amphibole . . . was the sole cause of the vast amount of mesothelioma we were seeing.[35]”

Plaintiffs’ Consolidated Response to All Motions to Exclude General Causation Opinion Testimony That Chrysotile Asbestos Can Cause Mesothelioma, filed in Gasner v. A.O. Smith Corp., No. 2004-03964, In the District of Harris County, 11th Judicial District, Texas, available at (citing Egilman affidavit, and in endnote 34, a letter from Irving J. Selikoff, M.D. (dated July 31, 1973), Ex. 31 to plaintiffs’ brief).

Dr. Irving Selikoff, who did so much to bring about an awareness of the hazards of asbestos, also did much to suppress the differences between and among the various mineral types of asbestos fibers.  And plaintiffs’ lawyers have continued to press this issue in order to make out their case for “every exposure” counts against low-exposure chrysotile defendants.

When Selikoff’s biography is written, this issue must be confronted directly.  Why was someone who so dedicated to public and worker health willing to take such liberties with the historical and scientific record?

The disinterested historical inquirer may observe that the companies that imported amosite and crocidolite into the United States were generally “judgment proof” in American courtrooms.  South African courts refused to acknowledge the validity of American judgments.  Plaintiffs’ lawyers, and their union sponsors, worried that chrysotile suppliers would escape liability and harsh regulation if the extent of amosite and crocidolite use, and its much greater hazardous, were appreciated.  One inference the disinterested observer might draw is that Selikoff was intent upon treating all fibers alike to advance a regulatory and litigation agenda that had nothing to do with science.

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