When does substitution make sense? To most of us, as consumers, either personally or professionally, the decision
regarding whether to purchase a product generally involves the interaction of three basic factors: cost, performance
and safety. After establishing minimum criteria for each of these parameters, we evaluate which product gives us
the best value for the money. We chose to substitute one product for another only if, after careful comparison, it is
netly superior to the original product in most or all of the established criteria.
While this fundamental tenet of consumer behavior remains the basis for most purchasing decisions in modern economies, over the last 20 years, governments have become increasingly active in establishing minimum criteria, particularly in relation to product safety. By extension, and through the activities of national and international health authorities, the notion of substituting less hazardous materials, where feasible, has become an integral element of industrial hygiene policy.
Regulatory inconsistency
For the most part, government interventions of this nature have led to a safer society. However, in the case of present-day applications of chrysotile asbestos, the system has failed, throwing the inherent wisdom of consumer behavior way off course.
In many cases, consumers have unwittingly been used to test unproven technologies and duped into believing that these asbestos-free products are by definition risk-free and environmentally friendly. In industry, workers often operate under a similar false sense of security and can often fail to take appropriate preventive measures. Consequently, they may be subjected to high exposure environments - which would not be the case if they were working with chrysotile asbestos.
"Eager to douse the dangers of asbestos, the Agency inadvertently actually may increase the risk of injury American face."
U.S. Fifth Circuit Court of Appeals Ruling Against the EPA's Asbestos Ban (p. 35)
The case of friction materials
The case of asbestos in friction materials is a text book example of how the threat of more stringent regulation is driving the market place to find replacement materials at whatever cost. The EPA's announcement in the 1970's that it intended to introduce a ban and phaseout of all uses of asbestos sent auto and friction manufacturers scrambling in search of adequate substitutes. Because of the importance of the U.S. market and the international nature of the automotive industry, this search had international repercussions. The search for substitute materials cost manufacturers, and ultimately consumers, hundreds of millions of dollars.
However, many friction material experts maintain that there is no convincing evidence that these materials are superior in any of the critical parameters. In fact, with regard to OEM (original equipment) applications, they draw attention to recent scientific evaluations of the fibrogenic and carcinogenic potential of many materials used to substitute chrysotile asbestos in friction materials.
In terms of after-market replacements for vehicles originally designed for asbestsos linings, friction experts have also raised very real concerns regarding the reliability and performance of substitute friction materials, particularly in trucks and other heavy vehicles. These concerns are echoed in a recent letter to the EPA in which General Motors (G.M.) states that using non-asbestos brake linings as replacement parts in vehicles that were originally designed with asbestos-containing linings can result in serious brake system performance compromises. G.M. urges the Agency to address this important issue. The EPA threat of banning asbestos forced the U.S. automotive industry to develop, at tremendous cost, new braking systems using alternative fibres. As a result, what consumers got was more expensive brakes, no improvements to performance, and brake linings which still contain carcinogenic materials.
Common sense tells us that if buyers, in this case both manufacturers and end users, had had the benefit of thorough cost-benefit evaluations of substitute materials, they would have chosen to stay with chrysotile products. Recent pronouncements by OSHA scientists in the U.S. that "glass fibres may be as potent or even more potent than asbestos" underscore the folly of U.S. regulatory policies on chrysotile asbestos.
Similar problems are being experienced when attempting to find substitutes for other presnt-day chrysotile applications. This year, a Danish building products company faces claims totalling in the millions as a result of home owners being supplied defective corrugated roofing sheets. The faulty sheets, all produced between 1985 and 1987, were manufactured using non-asbestos technology developed by the company. Similarly, performance failures have been reported with the use of non-asbestos gaskets in high temperature applications. These failures have resulted in worker injury and in some cases death. The risks posed by these more expensive and technically inferior products underscore the dangers of unqualified substitution and the need for stringent testing before a product can be marketed.
"All fibres that are respirable and biopersistent must undergo testing for carcinogenicity to the same degree as that required for asbestos until data supporting a lesser degree of control become available."
International Programme on Chemical Safety (Health Criteria 151, 1993), published under the joint sponsorship of UNEP, ILO and WHO
Accepting the burden of responsibility
In its Convention 162 and its code of practice, Safety in the Use of Asbestos, the ILO has stated that prior to replacing asbestos with substitute materials, the competent authority has a responsibility to scientifically evaluate whether the proposed alternatives are harmless or less harmful. It recommends that primary consideration should be given to their associated health hazards, technical performance and economic viability. Unfortunately, as we have witnessed in the United States, the 'competent' authorities have been less than competent in meeting this burden of responsibility.
The only way to prevent the application of inappropriate regulatory measures is for authorities to accept this responsibility by setting minimum standards, which apply equally to all materials, and by mandating pre-market testing for both performance and safety. No attempt to restrict one substance should be undertaken until full consideration has been brought to the economic, performance and safety characteristics of proposed substitutes.
Rigorous performance and safety standards
The Asbestos Institute's questioning of the logic of inconsistently applied control standards does not mean that we endorse more lax standards for chrysotile asbestos - quite the contrary. We are working hard to ensure that international standards relating to the protection of workers are respected wherever chrysotile asbestos is used. However, we do believe that the interests of workers and the general public will be best served if these rigorous performance, health and safety standards are used as a bench mark to evaluate all respirable and durable fibres. As the last few years have demonstrated, unqualified substitution is unsound public policy which often increases the risks to public and workers.
Scott Houston
Director General
Following the overturn of the U.S. Environmental Protection Agency's (EPA) ban and phase out rule of asbestos by the Fifth Circuit Court of Appeals in October 1991, it became apparent that erroneous statements were circulated on an international basis regarding the true facts about this court decision. For example, it was reported that asbestos use remains unlawful in the USA and/or that the overturn applies only to those states comprising the Fifth Circuit (Texas, Mississippi & Louisiana). Such statements, of course, are plainly wrong. The court's decision applies throughout the entire United States.
No U.S. prohibition on manufacture and use
Asbestos products that were exempted from the ban rule by the court decision on October 18, 1991 included:
The court decision did, however, permit EPA to ban asbestos products that were not being manufactured, imported or processed on the date the rule was published (i.e. July 12, 1989). Following extensive investigation by EPA and submission of documentation by the U.S. asbestos industry, the agency confirmed on November 5, 1993 that the following additional asbestos products are no longer subject to the ban rule:
OSHA sets new asbestos standards
In addition to EPA, the other major regulatory agency in the USA, is the U.S. Occupational Safety and Health Administration (OSHA). OSHA does not have the authority to ban products, but rather it is the agency that regulates occupational exposures to substances in the workplace. In 1986, OSHA published asbestos standards for general industry and construction, both of which included a permissible exposure limit (PEL) for all fibre types of 0.2 f/cc. These standards were challenged in the U.S. court system by two labour organizations and the Asbestos Information Association/North America (AIA/NA). On August 10, 1994, OSHA published its final standards to amend the 1986 regulations after earlier modifications had been made in 1989 and 1990. Most of the revision in these amended standards were in follow-up to court directed actions.
As was expected, the primary revision in the new rules is a reduction of the eight-hour time-weighted-average PEL to 0.1 f/cc for all fibre types. In this regard, the U.S. remains the only industrialized nation that fails to recognize the difference in health effects between chrysotile and the amphiboles. Upon publication, the head of OSHA, Joseph A. Dear, emphasized that the new rules do not require asbestos removal but instead focus on improving management of in-place asbestos.
Industry challenges OSHA requirements
While the major change in the general industry rule only lowered the PEL, OSHA did impose ancillary requirements for any construction activity involving asbestos-containing material (ACM includes all products with 1% or more asbestos). And, not unexpectedly, because of these unnecessary and costly requirements - regardless of exposure levels - for asbestos maintenance, repair and removal, OSHA's latest rules have again been challenged. To date, 17 court challenges have been filed by 14 industry and three labour groups, including AIA/NA. The legal challenges of OSHA's new asbestos rules will be reviewed by the U.S. Court of Appeals for the Fifth Circuit. It is significant that this is the same court that overturned EPA's asbestos ban and phase out rule.
As was the case with EPA mentioned above, comments have been reported that OSHA's new rules are tantamount to a ban of asbestos in the USA. This assertion is totally false. While certain revised construction requirements would be onerous were they permitted to stand, they by no means will result in an asbestos ban. Essentially, the new requirements are not scheduled to become effective until April 1995. With the strong court challenges pending, it is fully expected that these new OSHA regulations will either be changed by OSHA through administrative action in the near future or the agency will be subsequently forced to make changes by court mandate.
U.S. asbestos consumption on the rise
In the meantime, major uses of asbestos in the USA include the manufacture of friction materials and roof coatings. Other asbestos products being imported and installed include asbestos-cement pipe and sheets and gaskets. In 1993, the U.S. Bureau of Mines reported that the U.S. consumed 31,636 metric tons of asbestos, a 7.5% increase from 1992 levels.
Bob Pigg
President, AIA/NA
Mineral wools:
Glass microfibres (specialty applications) : 1.0 f/cc
Natural mineral fibres:
The German Committee for Hazardous substances (AGS) will be responsible for the final appraisal of MAK classifications and for recommending appropriate control measures based on the approved classifications. According to the report, the AGS had already issued (in 1992) a limit for fibre concentration in the workplace which sets a relatively high standard compared to other international regulations. Beyond that, the AGS plans to work on the further formulation of concise technical and organizational measures for protection, based on the regulation of hazardous substances.
The report also states that heat insulation using mineral wool products and made in accordance with established construction codes does not lead to a hazardous fibre concentration inside buildings, and that there will be no general need for dismantling and disposing of already mounted insulation. Although there has been no serious discussion of a future ban of MMMF insulation materials, there have been calls for a further reduction of the inhalable proportion of fibres and an increase in the biological degradability of mineral wool fibres in these products.
NIOSH estimates that 200,000 workers in the U.S. are potentially exposed to fibreglass. Studies indicate that exposure of users may exceed those of production workers. According to HHS, "the primary routes of potential human exposure are inhalation and dermal contact. Large diameter (greater than 3.5 µm) glass fibres have been found to cause skin, eye and upper respiratory tract irritation. Smaller-diameter fibres have the ability to penetrate the alveoli. This potential is cause for concern and is the primary reason that the fibres are subject to special controls." (Source: Seventh Annual Report on Carcinogens: 1994, U.S. Department of Health and Human Services, National Toxicology Program)
The Ministries ultimately recommended that RCF be added to the Canadian List of Toxic Substances, and that stakeholders be consulted regarding options to reduce the emissions of and exposures to RCFs. The process will identify and evaluate control instruments such as guidelines, codes of practice, voluntary agreements, market-based measures, as well as conventional command and control regulations.
The committee is comprised of representatives from the RCF industry, various levels of government and non- governmental organizations. Its first meeting took place in December in Ottawa. General guidelines for the consultation process were established and some discussion centered around the need for a code of practice. The committee is expected to meet several more times over an 18-month period.
Silicon carbide whisker is a finely spun ceramic compound which is used for insulation (e.g. furnace linings) and as a reinforcing agent in resins, metals and ceramics. Recent studies have demonstrated the potential toxicity of both aluminum oxide and silicon carbide whiskers. Both have been shown to produce a high tumour incidence in rats after intrapleural injection. Other in vitro studies have shown that the toxicity of silicon carbide whiskers may exceed that of crocidolite asbestos fibres. [Sources: Johnson et al. NATO Advanced Research Workshop on Mechanisms in Fibre Carcinogenesis. Albuquerque 1990; Vaughan et al. Environ. Res. 63:191-201 (1993)]
More carcinogenic than Œasbestos¹?
The report claims, based on a comparison of the carcinogenic potency of glass fibres and asbestos fibres [all types], that ³on a fibre-per-fibre basis, glass fibres may be as potent or even more potent than asbestos.²
Implications for the workplace
In line with the authors¹ conclusions regarding the similar potency of asbestos and fibrous glass they estimate, based on OSHA¹s risk assessment model for asbestos, that ³maintenance of average occupational exposures below 0.04 f/cc would result in an estimated risk of less than 1 excess lung cancer death per 1,000 over an occupational lifetime.²
The authors note that studies of the 11 U.S. fibrous glass manufacturing plants demonstrate that in most cases worker exposures are well controlled. However, they add, ³In our view, a candid disclosure about the potential risk of lung cancer is warranted. Workers should be warned about the potential hazards associated with exposure to these fibers. A cancer warning label affixed to glass wool products is currently required under the OSHA hazard communication standard.²
Negligible risk to the public
The authors clearly state that their concerns relate to the occupational environment and not to the general public. ³...the risk to consumers from home/institutional exposure to fiber glass insulation should be placed in proper perspective so that misplaced fear and apprehension about a presumably negligible risk does not occur.² [Source: PF Infante, LD Schuman, J Dement, J Huff. Amer J Ind Med, 26:559-584 (1994)]
The meeting was attended by 36 invited scientists and 11 observers from 12 countries. Some 70 other scientists were invited to submit relevant information prior to the proceedings.
While in the past, scientists and regulators spoke of the effects of 'asbestos', extensive evidence now exists to show that the various asbestos minerals (chrysotile and amphiboles) differ considerably in their propensity to increase health risks. More specifically, many of the papers presented confirm once again that chrysotile poses significantly less risk than amphibole varieties. As mentioned at the Workshop, this has important worldwide practical, social and economic implications.
The Executive Summary of the Work-shop concludes that "... no detectable risk, or an extremely low level risk of lung cancer associated with exposure to chrysotile at and below lifetime cumulative exposures of 30 f/mloyears (i.e. 1 f/ml for 30 years). No chrysotile-related increased risk was detected at considerably higher exposures in the mining sector."
The Workshop, held in the Channel Islands in November 1993, was organized by the Scientific Committee on Mineral Fibres of the International Commission on Occupational Health (ICOH) in collaboration with the WHO/ILO/UNEP International Program on Chemical Safety (IPCS). The papers presented have since been published in The Annals of Occupational Hygiene (Volume 38, No. 4, August 1994). Copies can be obtained from the publisher at the following address:
Elsevier Science Ltd.
The first, an animal inhalation study by McConnel et al.(1994), compared the effects on male Fischer rats of exposure to 10 mg/m3 of either chrysotile (equivalent to approximately 10,000 f/cc ) or crocidolite asbestos (equivalent to approximately 1,600 f/cc) for 6 hours/day, 5 days/week. While the results of these studies found that both types of asbestos studied cause time/dose-related progressive pulmonary inflammation, crocidolite asbestos was found to cause more severe inflammatory disease at an earlier time than chrysotile. This finding, along with their analysis of observed tumour growth led the authors to conclude that crocidolite is more fibrogenic and carcinogenic on both a mass and a fibre basis than chrysotile in the rat lung.
Another study by Churg & Vedal (1994) attempted to determine the mineralogical factors that relate to the appearance of asbestos-related disease in workers with heavy mixed exposures to amphiboles and chrysotile. Their analysis of the pulmonary fibre burden of 144 shipyard workers and insulators found that "the major residual fibre is amosite, and only amosite concentrations correlate with the presence of specific diseases, raising questions about the role of chrysotile in disease induction."
The third study, by Albin et al. (1994), analyzed postmortem lung tissue retention patterns among asbestos-cement workers. Based on the data, the authors indicated that chrysotile has a relatively rapid turnover in human lungs compared to amphiboles. Consistent with previous findings, fibre deposition and retention were thought to be increased by tobacco smoking.
McConnel et al., Comparison of the effects of chrysotile and crocidolite asbestos in rats after inhalation for 24 months. In Toxic and Carcinogenic Effects of Solid Particles in the Respiratory Tract, Ed. Mohr et al. ILSI, Washington D.C. (1994).
Churg & Vedal, Fiber burden and patterns of asbestos-related disease in workers with heavy mixed amosite and chrysotile exposure. Amer. J. Resp. Crit. Care Med. 150:3 (1994).
Albin et al. Retention patterns of asbestos fibres in lung tissue among asbestos cement workers. Occ. & Env. Med. 51:205-211 (1994).