Edition 1995-1
- Evidence of health effects of some natural and man-made fibres used in friction materials
- Editorial comment: In search of responsible rule-making
- A factual review of current asbestos regulations in the USA
Actual risks are found from long-term, usually heavily-exposed worker health statistics. For lower exposure levels, estimated risks are calculated from a mathematical model. Some of these models are known to be very biased, and different exposure statistics may be used. Perceived risks are based on our beliefs, which often are in error. Decisions regarding the type of risk data and the mathematical model used can ultimately have a significant impact on the nature and severity of regulatory controls. While governmental agencies are expected to carefully consider all risks and all benefits before issuing regulations, at times, political and other pressures predominate.
For example, while available health statistics (actual risks) do not reliably confirm any asbestos risk for brake mechanics, in the U.S., the Occupational Safety and Health Administration (OSHA) brake mechanic data was used to estimate a mechanic's lifetime health risk at 0.18/1,000 for a male smoker. In its failed ban attempt, EPA used brake mechanic exposure data but applied it to a risk assessment model based on health data from insulation workers using amphibole fibre. By not distinguishing between fibre types and industrial processes used, the U.S. EPA has greatly overstated the risks of chrysotile asbestos.
While replacing chrysotile asbestos from our brake linings with other fibres will not reduce health risks by any measurable amount, without adequate research and product testing, substitution could increase both health risks to workers and traffic safety risks due to brake failure or improper performance.
The 1993 World Health Organization Environmental Health Criteria 151 states that "all fibres that are respirable and biopersistent must undergo testing for toxicity and carcinogenicity." Many fibres used in non-asbestos brake linings have been flagged at WHO and ILO meetings as "probably or possibly carcinogenic." These include refractory ceramic fibres, Kevlar pulp, mineral wool, glass fibres, phosphate fibres, and carbon fibres. Rigorous environmental control measures are recommended when friable mixtures (such as brake lining preforms) contain over 1% of these fibres.
Literally hundreds of different natural and synthetic fibres are now used in brake linings. Most friction material manufacturers cannot afford the cost of testing all of their products for fibre release during manufacturing, brake usage, and replacement. Considering today's litigious society, can they afford not to test them?
I have performed diagnostic studies on several fractured heavy truck brake drums over the past seven years. All of them had their root cause in non-asbestos brake blocks. Most of them involved light brake drag applications from highway speed, with low braking temperatures. In laboratory tests of these 'problem' non-asbestos brake linings, new brake drums have fractured with no more than a few hundred gentle, low-temperature brake applications.
Serious accidents involving passenger cars and light trucks have also been linked to the use of non-asbestos brake linings. Most have resulted from poor brake balance, where rear wheels skid unexpectedly. This may occur during the first few brake applications in cool, wet weather conditions. The 1987 American Society for Mechanical Engineers (ASME)/EPA study on asbestos replacement in brakes noted the problem of developing a good replacement drum brake lining for existing cars - those that originally used asbestos-based brake linings. A NHTSA study also showed that non-asbestos drum brake linings were more variable in their effectiveness than most asbestos-based brake linings.
Many new vehicles are now equipped with anti-lock braking systems (ABS). When working properly, ABS can reduce accidents due to unbalanced brakes or unusual road surface conditions. However, accidents continue to be reported which appear to result from ABS failures. It is too early to tell if our complex and costly ABS systems will have long-term benefits that exceed their risks.
"What we cannot ignore is that the EPA failed to study the effect of non-asbestos brakes on automotive safety, despite credible evidence that non-asbestos brakes could increase significantly the number of highway fatalities, and that the EPA failed to evaluate the toxicity of likely brake substitutes."U.S. Fifth Circuit Court of Appeals Ruling Against the EPA's Asbestos Ban (p.42)
The use of substitute fibres in brake linings causes a complex risk-benefit situation; one that severely challenges our vehicle manufacturers. They can, and have, designed new vehicles to have safe brakes with non-asbestos brake linings. This has involved 'balancing' existing brake systems for the new brake linings, designing new brake assemblies, and even adding anti-lock braking systems. A major vehicle manufacturer reported brake lining costs, brake development testing costs, and warrantee expenses; all have risen substantially during the move to non-asbestos brake linings. This is in sharp contrast to non-asbestos brake lining ads that claim they are 'cost-effective.'
We need to know how much respirable fibre is in the wear debris of all brake linings, asbestos and non-asbestos. This is not known for most non-asbestos brake linings. Asbestos-based drum and disc brake linings wear by a process that releases only a tiny fraction of 1 percent of the original asbestos, with 99.7% converted into other products such as forsterite, a material which is non-carcinogenic in animals. Non-asbestos friction materials initially contain fewer fibres, but no meaningful database exists on their respirable fibre emissions.
Our problems are international. Unfortunately, any meaningful resolution requires international communication, cooperation, and consensus. This will not be easy to obtain. A first step is to openly discuss the issues. Is it too much to expect both safe brakes and safe workplaces?
Mr. Anderson is active in several engineering societies, and is a co-author of the ASME/EPA report on the feasibility of replacing asbestos in automobile and truck brakes. Prior to becoming an independent consultant, Mr. Anderson worked for 30 years for the Ford Motor Company, conducting research into various aspects of friction material performance and safety.
(1) ILO Safety in the use of mineral and sythetic fibres, 1989, p. 40
(2) IPCS Environmental Health Criteria 151, Selected Synthetic Organic Fibres, WHO, l993
(3) Saracci, R. et al.(1984) Brit J Ind Med. 41:425-436
(4) U.S. EPA, Status Report FTI-OTS-0386-0486, (1986)
(5) Davis, JMG et al.(1983), Biological effects of man-made mineral fibres, Euro Reports and Studies: 81:p. 124
(6) Huuskonen, M.S. et al.(1983) Environ. Res. 30:291-304
(7) Pott, F. et al.(1976) Ann. Anat. Pathol. 21:237-246
In order to remain competitive in our rapidly evolving global economy, companies must ensure that regardless of the country of origin or use, their products meet international standards. Today, such standards imply much more than traditional government norms for product safety. In the marketplace and in the regulatory arena, quality is judged not only in terms of product safety and performance, but also in terms of environmental impact and industrial hygiene standards. Increasingly, the ability of a primary or secondary manufacturer to achieve these implicit and explicit environmental and industrial hygiene standards is critical to its success or failure in the highly competitive global economy.
While national and international regulations are important mechanisms for the assessment of quality, they are by no means the only ones. The globalization of business has also led to the globalization of labour unions which are increasingly active at the international level. Other, non-governmental organizations (NGOs) such as environmental groups, professional associations and consumer groups, all of which operate internationally, are also instrumental in providing checks and balances in developing as well as industrialized countries.
Perhaps even more important than these external forces leading international industry towards more uniform industrial hygiene and environmental standards, is the strong drive from within industry itself to achieve parity between the developed and the developing world. This happens at several levels and for multiple reasons.
At a very basic level, there is an ethical imperative for companies in all countries to provide safe working environments for their employees. Above and beyond the notion of being a good corporate citizen, careful attention to worker health and safety throughout the product life-cycle makes sound economic sense. Prevention has been demonstrated to be less costly than remediation. Productivity losses, potential litigation, bad publicity, increased costs resulting from the rushed implementation of health and safety controls, and the threat of regulatory backlash all increase in likelihood for companies which do not take proactive measures. It is also likely that regulations which are imposed as a backlash against poor conditions will be far more severe and damaging.
Because such severe restrictive measures would be imposed on the industry as a whole, not just those companies with substandard industrial hygiene and environmental controls, at the local and national level there has been, and there will continue to be growing pressure on those companies which do not meet international standards. Similarly, at the international level, justified concerns that problems in one country will have regulatory or media repercussions in other countries places additional pressure for international compliance, in both industrialized and developing countries.
For the asbestos industry, multinationals have had an important role to play in the globalization of industrial hygiene. For the most part, their environmental and health policies are set at their head office and then applied uniformly in all countries in which they operate. In addition, their leadership can spur smaller companies to match the standards they have set. Multinationals have helped set up national industry associations; they have worked with governments and unions in developing appropriate regulations consistent with national standards; and they have provided assistance to smaller companies in achieving these standards.
As in most industries, not all companies have embraced the controlled-use philosophy. This is a matter of concern not only for workers in those factories, but also for the industry as a whole. The issue of dust control in the small- and medium-sized business sector is being openly discussed by government, industry and trade unions in Brazil, as well as by other suppliers of asbestos to the Brazilian market. ABRA is working closely with these key players in developing meaningful and practical solutions to this problem.
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The Cana Brava mine's state of the art controls
SAMA is the Brazilian company which operates the Cana Brava asbestos mine, the largest in Latin America,
located 200 km north of Brasilia. All operations are carefully controlled to ensure that occupational and
environmental safety and control standards are met. Adding to this, the company has provided and manages an
extensive program for the reclaiming of the surrounding area of the mine, including soil, waters and
vegetation.
1994 average fibre counts at Cana Brava
Asbestos-cement industries make tremendous strides
Originally set at 4 f/cc three years ago, Brazil's exposure limit value was lowered to 2 f/cc. In the asbestos-cement industry, as a result of a voluntary agreement between industry, labour and government, the occupational exposure limit was further lowered to 1 f/cc, with an agreement to bring it down to 0,5 f/cc in 1995. Many A/C manufacturing facilities have already met or surpassed this standard.
Established in 1989 and endorsed by industry, labour and government, the National Convention for the Use of Asbestos in Safe Conditions identifies a number of control measures to which Brazilian industry must adhere. These include: