Living in a state, California, beset by the actuality of drought and the real, imminent threat of earthquake, must be scary. And still, Californians seem to relish increasing the appearance of risks everywhere. The state has astonishing epistemic insights, knowing risks not known to anyone else, through its Proposition 65. And then there are legislative fiats that posit risks, again unknown outside California. David Lazarus, “Berkeley’s warning about cellphone radiation may go too far,” Los Angeles Times (June 26, 2015). And now there are killer crayons from China. Victoria Colliver, “Asbestos fibers found in some crayons, toys from China,” SFGate (July 8, 2015).
Ms. Colliver is largely the uncritical conduit for an advocacy group, which speaks through her, without any scientific filter:
“Environmental health advocates said there is no safe level of exposure to asbestos, a group of naturally occurring minerals with microscopic fibers. The fibers can accumulate in the lungs and have been linked to cancer and other health problems.”
Id. At best, some scientists, mostly of the zealot brand, say that there is no known safe level of exposure to asbestos, but this is quite different from saying there is known to be no safe level. Honest scientists will acknowledge a dispute about whether low-level exposures are innocuous, but uncertainty about safety at low doses does not translate into certainty about unsafety at low doses. And the suggestion that fibers can accumulate in the lungs may be true for occupational and paraoccupational exposures, but human beings have defense mechanisms that block entry by, and rid the lungs of, asbestos fibers. At the cellular and subcellular level, humans have robust defenses to low-levels of carcinogens in the form of DNA repair mechanisms. Of course, as wild and unpredictable as little children can be, they rarely inhale crayons. If they do, asbestos won’t be their problem. (To be fair, one of the products tested was a powder, which could be aerosolized, but there is no quantitative assessment of the extent of asbestos in this powder product.)
Ms. Colliver’s source is a report put out by Environmental Working Group Action Fund, the website for which does not acknowledge any scientific oversight or membership. Colliver’s “hot quotes” are from Richard Lemen, who is a regular testifier for the asbestos litigation industry.
What you will not see in Colliver’s “science” coverage is that there is no mineral asbestos; rather it is a commercial term for six different fibrous naturally occurring minerals. Five of the asbestos minerals are amphiboles – crocidolite (blue), amosite (brown), tremolite, anthophyllite, and actinolite. The remaining mineral fiber is chrysotile. There are, to be sure, many other fibrous minerals, but none with any suggested carcinogenicity, other than the non-asbestos zeolite mineral erionite. The most serious health effect of some kinds of asbestos is mesothelioma, a malignancy of the serosal tissues around the lung, heart, and gut. Crocidolite and amosite are by far the major causes of mesothelioma.
Although Colliver does not link to the EWG’s report, it is easy enough to find the report on the group’s website. See Bill Walker and Sonya Lunder, “Tests Find Asbestos in Kids’ Crayons, Crime Scene Kits” (2015). Most of the products tested had no detectable asbestos fiber of any kind. The EWG report provides no quantification of the findings so it is hard to assess the extent of the asbestos present. The report does provide the identity of the fibrous asbestos minerals present: tremolite, anthophyllite, actinolite, which suggests that the fibers were present in low levels in the talcs used as binding agents or mold release for the crayons. The EWG report fails to provide quantitative information on the distribution of morphology of the so-called fibers. The biologically dangerous fibers have a high-aspect ratio. Importantly, crocidolite and amosite, which collectively are the major causes of mesothelioma, were not found.
Assuming the report is correct, the hazard to children is remote and incredibly speculative. Fibers in the crayons would not be readily aerosolized, and the fibers could not represent even a theoretical hazard unless they were inhaled. The only disease for which low exposures is even a theoretical concern is mesothelioma. Back in 2000, a similar scare erupted in the media. At that time the Consumer Product Safety Commission tested the crayons, and concluded that the risk of a child’s inhaling asbestos fiber was “extremely low.” No airborne fibers could be detected after a simulation of a child’s “vigorously coloring” with a crayon. U.S. Consumer Product Safety Commission, CPSC Staff Report on Asbestos Fibers in Children’s Crayons (2000). The business of defining what counts as an asbestos fiber, as opposed to a non-carcinogenic particle, is complicated and sometimes controversial. See Bruce W. Case, Jerrold L. Abraham, G. Meeker , Fred D. Pooley & K. E. Pinkerton, “Applying definitions of “asbestos” to environmental and “low-dose” exposure levels and health effects, particularly malignant mesothelioma,” 14 J. Toxicol. Envt’l Health B Crit. Rev. 3 (2011) (noting lack of consensus about the specific definitions for asbestos fibers).
As for low-exposure alleged risks, the evidence varies by disease outcome. For lung cancer, there is actually rather strong evidence of a threshold. And lack of conclusive evidence of a threshold below which mesothelioma will not occur is hardly evidence that mesothelioma could result from any theoretical exposure postulated from children’s use of the crayons. The business of attributing a case of mesothelioma to a low-level previous exposure is, of course, very different from predicting that a very low level exposure will have a public health effect in a large population. Asbestos minerals occur naturally, and rural and urban residents, even those without occupational exposure, have a level of asbestos that can be found in their lung tissue. There is, however, a business of attributing mesotheliomas to low-level exposures, that has become a big business indeed, in courtrooms all around the United States. The business is run by expert witnesses who regularly conflate “no known safe level” with “known no safe level,” just as Ms. Colliver did in her article. What a coincidence! See Mark A. Behrens & William L. Anderson, “The ‘any exposure’ theory: an unsound basis ·for asbestos causation and expert testimony,” 37 Southwestern Univ. L. Rev. 479 (2008); Nicholas P. Vari and Michael J. Ross, “State Courts Move to Dismiss Every Exposure Liability Theory in Asbestos Lawsuits,” 29 Legal Backgrounder (Feb. 28, 2014).
