Australian construction workers, engineers and designers need to understand the risks associated with exposure to asbestos and other hazardous materials.
Asbestos was used until the early 1980s in building materials, vehicle brakes and as lagging (insulation) in mechanical and electrical equipment.
Asbestos in various forms was used in submarines, naval vessels and military equipment to control the risk of fire and heat. It was used initially in nuclear plants to separate equipment operating at extreme temperatures.
The exposure to asbestos in Baryulgil, a tiny Indigenous community on a ridge that rolls away to fertile grazing country along the Clarence River near Grafton in northern New South Wales, was perhaps the highest in the world. But the mine’s operator is alleged to have failed to tell residents or workers of the risks until decades after they were known.
When the health impacts were finally revealed, compensation was almost non-existent. Health records were hidden and autopsies rare. Some speculate that all this was deliberate, that the manufacturer relied on the fact Indigenous workers would die early anyway, and the cause would not be questioned because it would be blamed on alcohol or cigarette use. They banked on the fact no one would notice how few men in the cemetery were aged over 40.
Australia used more asbestos per person than any other nation on Earth from the 1940s through the 1960s.
Like the long battle for authorities to recognize the damaging effect of tobacco smoking on health, the health related issues relating to the exposure to asbestos were at first and for many decades, they were considered to be unproven by medical research. Therefore, very little action was taken, and research which was highly critical of exposure to the material was not referenced or acted upon.
Two doctors were responsible for raising the alarm about the asbestos risk at Wittenoom, Australia's largest asbestos mine. In 1948, Dr Eric Saint, the area flying doctor, was newly arrived from England and so was aware of the health risks from asbestos from his experience there. A few years later in the late 1950s, Dr Jim McNulty was working as the mine's medical officer. Both men were appalled at the conditions and both raised the alarm about the health risk for the workers.
A key turning point came in 1964 at an international conference in New York on the biological effects of asbestos. Dr Irving Selikoff’s research became a landmark by finding high levels of asbestosis among American insulation workers who were not employed in the asbestos industry but only used asbestos insulation products in their building, construction and maintenance work. The asbestos hazard was shown to have spread throughout the built environment to anyone who handled the industry’s products.
In the case of asbestos, manufacturers of building products were aware of alternate natural fibres such as cellulose (cardboard), which had the potential with some innovation to completely replace asbestos fibres, some 20 years before they took action to replace asbestos in their manufacturing processes. Eventually, asbestos fibre was replaced by cellulose fibre in building sheet materials. Fibreglass and mineral wool replaced asbestos in insulated materials, ceramics replaced asbestos brakes, and glass fibre replaced asbestos in concrete reinforcing and epoxy resins for fibreglass.
Clearly, industry and manufacturers have been found to be reluctant to utilize alternatives which are less toxic, unless there is overwhelming “scientific” evidence of the potential hazards. This experience appears to closely mirror the very familiar “no ill health effects” defense of the tobacco industry. The time lapse between a product, process or material being identified as a potential carcinogen or cause of serious health impacts, to becoming a restricted or banned substance took circa 30 to 50 years. In the case of asbestos, this measure depends on where you determine that health issues should have been well-known to the scientific, medical and industrial communities.
The model Work Health and Safety (WHS) Regulations set out a framework for the management of asbestos materials in workplaces including: the training of all workers at risk of encountering asbestos during their work, naturally occurring asbestos, the removal of asbestos, and the licensing and competency requirements for asbestos removalists and assessors. Information on identifying asbestos, creating an asbestos register, and managing the risks of asbestos in the workplace can be found in the Australian model Code of Practice: How to Manage and Control Asbestos in the Workplace.
Today a number of chemicals and materials are considered to be highly likely to be causational in poor health outcomes. The cancer research arm of the World Health Organization recently announced that glyphosate, the world’s most widely used herbicide, is probably carcinogenic to humans. That is a serious issue since modern farming techniques often require the wide spread use of pesticides.
This announcement comes as a shock to many in building maintenance and the agricultural industry. The announcement also received substantial push back from the producers and suppliers of these and related products despite the fact that the assessment was done by the International Agency for Research on Cancer (IARC) in Lyon, France. A panel of international experts convened by the agency reported the findings of a review of five agricultural chemicals in a class known as organophosphates. A summary of the study was published in The Lancet Oncology. Glyphosate is the world’s most widely produced herbicide by volume. It is used extensively in agriculture and is also found in garden products in many countries. The chemical is an ingredient in some weed killers.
Studies dating back to the 1980s have indicated that despite the low overall mortality rate from heart disease, cancers of the lung, oesophagus, bladder and colon, farmers in many countries appear to have higher rates for Hodgkin’s disease, leukaemia, multiple myeloma, non-Hodgkin’s lymphoma, and cancers of the lip, stomach, prostate, skin, brain, and connectives tissue compared with the general population. The strongest links of cancers in agricultural workers are to herbicides.
Farmers and those in rural communities have higher rates of cancer than their urban counterparts, and these are even more pronounced for men.
Some groups are at greater risk of prostate cancer. For example, detailed experiments showed that glyphosate mimics the action of oestrogen, and uses the same molecular pathways as the natural hormone to promote proliferation of the damaged cells. They also found that glyphosate had synergistic effects in enhancing “damaged” breast cell growth in combination with genistein, a common phytoestrogen in soybean.
New research shows that the low levels of glyphosate found in human urine is linked to the issues in human breast cells, confirming the damaging potential of the herbicide known since the 1980s.
“There have also been investigations into the impacts of glyphosate-containing herbicides on organisms living in river, streams and coastal waters," according to Friends of the Earth Europe.
"Micro-organisms are vital to marine and freshwater ecosystems, because they form the basis of food chains. In laboratory experiments, the growth and species composition of microbial populations from marine waters was disturbed at levels of glyphosate typical of those caused by run-off from the land. Similar effects were found on microbial populations from freshwater systems. Another study found that photosynthesis in freshwater cyanobacteria was inhibited by glyphosate-containing herbicides, while tiny aquatic animals called Rotifers were found to have reduced life expectancy and reproductive rates, longer development times and lower overall populations.”
The EU and national governments are to immediately start a monitoring programme for glyphosate in food and feed, including imported animal feed crops such as genetically modified soy. Levels of glyphosate (and its breakdown product AMPA) in the environment should also be monitored, covering aquatic systems and soil. These monitoring programmes should be comprehensive and the results should be made available to the public without delay.
The organic compound 2,4-D has been used for 70 years to control weeds in wheat, corn and soybean fields as well as gardens and lawns. The US sprayed about 16 million kilograms of the chemical in 2012, according to US government estimates.
"In 2001-2003 there was significantly higher incidence of melanoma (associated with sun exposure) and lung, head and neck, and lip cancers (associated with smoking) in Australian rural and remote areas than in metropolitan areas," said Dr Mark Short of the Institute's Health Registers and Cancer Monitoring Unit.
'Men in rural and remote areas in particular, also had significantly higher rates of cancers diagnosed in advanced stages, which underscores the importance of getting regular health checks from their doctors to increase the likelihood of early detection of cancer."
Other chemicals and materials currently considered to be potential cancer causing agents include:
Benzene has an implied role in leukemia. It is commonly found in construction solvents, as well as paints, inks, adhesives, rubbers, glues, stain removers, and furniture wax. It has been used as an antiknock additive in gasoline. Rubber workers exposed to benzene have been shown to have a tenfold increase in leukemia. Benzene was present in some liquid membranes used in the construction industry, and in some sheet materials.
Polyvinyl chloride, a plastic used in pipe, electrical wire and cable, home furnishings, toys, packaging, upholstery and auto parts, is made from vinyl chloride. It causes liver cancer, with a latency period which is 15 to 40 years. Construction workers should avoid inhaling smoke from burning foam or plastic.
Methylene chloride is a popular solvent for resins, fats, and waxes and is used in paint, thinners, removers, adhesives, film, plastics, inks, foams, hairsprays, air fresheners, and printed circuit boards. Exposed workers have an increased incidence of pancreatic and liver cancer deaths. It may produce liver and lung health issues in animals. The US Environmental Protection Agency considers it a probable human carcinogen.
Trichloroethylene (TCE) is used for degreasing metal parts. It has been found in typewriter correction fluids, paint removers and strippers, adhesives, and spot removers. TCE in animals may produce liver and lung issues, kidney issues, testicular issues and leukemia in rats. Exposed workers may have a high incidence of bladder issues. It is probably a human carcinogen.
Tetrachloroethylene and perchloroethylene have been used in dry cleaning, degreasing metal, suede protectors, paint removers, water repellents, silicone lubricants, adhesives, spot removers, wood cleaners and many products used by hobbyists. In animal studies, liver and kidney issues and leukemia have been produced at a sufficient level to cause the EPA to classify it as an animal carcinogen and a “probable human carcinogen.”
Polychlorinated biphenyls (PCBs) include 209 related chemicals and are found in transformers manufactured before 1977, older welding equipment, x-ray machines, refrigerators and in fluorescent light fixtures. In laboratory tests, PCBs cause liver, pituitary, and gastrointestinal tumors, as well as leukemia and lymphomas. The Environment Protection Authority in the US, considers PCBs probable human carcinogens.
Methyl ethyl ketone (MEK)
MEK is a colorless, volatile, organic solvent with a pleasant pungent odor akin to lacquer thinner. It is commonly used as a cleaning solvent in construction. Chronic inhalation of MEK vapors at concentrations in the range of 100 to 300 PPM and higher is toxic to the adult central nervous system. MEK also has the peculiar property of potentiating the neurotoxicity of other organic solvents. MEK has a remarkable ability to enter the body through intact human skin.
Chlorinated hydrocarbons: dioxins and furans
Dioxins and furans are found in chlorinated organic solvents, pesticides, weed killers, wood preservatives, such as pentachlorophenol, and charcoal starter. They can still be found in the herbicide 2,4-D and 2,4,5-T. The US Environmental Protection Agency considers dioxin to be a "cancer promoter" and classifies it as a probable human carcinogen responsible for leukemia, lymphoma, Non-Hodgkins lymphoma and soft-tissue sarcomas which have latency periods of 20-plus years. Unfortunately, today's physicians often fail to inquire about potential causation when the immediate need is to provide care, but all such cancers should be closely scrutinized to determine a toxic starting point.
Long latency periods are a significant but not insurmountable challenge in proving toxic chemical exposure cases. A successful protocol to map a leukemia cluster in Northern California proved that dioxin laced pentachlorophenol was the cause of four leukemias in employees of a small lumber mill, a 20-year-old bucket of Woodlife. The match was not perfect, but after 20 years it was able to be proven that a correlation factor of 80 per cent was indicated, and ended any doubt to the validity that exposure to Woodlife could cause serious health issues.
Construction laborers and landscaping crews who regularly used Weed B Gon and who have had chronic exposure are progressing toward a time when soft tissue issues, blood disorders, and other health issues may be presenting, 20 years after the fact. That was learned from a Seveso dioxin explosion and has been confirmed. The fact is, many who will are diagnosed with these diseases may never learned that they are suffering because of workplace exposures that occurred years ago.
Fibreglass is now used for thermal insulation of industrial buildings and homes, as acoustic insulation, for fireproofing, as a reinforcing material in plastics, cement, and textiles, in automotive components, in gaskets and seals, in filters for air and fluids, and for many other miscellaneous uses. More than 30,000 commercial products now contain fibreglass.
As asbestos has been phased out because of health concerns, fibreglass production has been rising. In 1994, the US Department of Health and Human Services reported to Congress that fibreglass is "reasonably anticipated to be a carcinogen" with certain types of exposure. It must now be labeled a potential carcinogen in the US.
For every 100 men who die of prostate cancer in a metropolitan area of Australia, such as Melbourne or Sydney, 121 men will die in rural Australia. Various factors may include lack of awareness and education about prostate cancer, distance from testing and treatment, poor physician awareness and limited access to specialists (such as urologists).
The Vietnam Veterans Association of Australia states that veterans have a 53 per cent higher mortality rate from prostate cancer than the average population. Their exposure to Agent Orange and other chemicals has been well documented.
A recently published international study showed that firefighters have a 28 per cent higher risk of prostate cancer.
Firefighters are exposed to many construction materials which may vaporize when burnt.
Naphthol and 1-pyrenol, polycyclic aromatic hydrocarbons, cyanides, hydrogen cyanide, polycyclic aromatic hydrocarbons, volatile organic compounds and formaldehyde are all present in building fires. Firefighting foams, especially for aircraft fires, may have harmful ingredients which have been shown to accumulate in areas where fire training for aircraft has been carried out.
As well as chemical exposures, construction workers may be exposed to radioactive materials when installing medical equipment, nuclear reactors, or when mining in the presence of radioactive infused materials, which may have occurred naturally.
Is it time for a review of the availability of these toxic materials? In the light of the free trade agreements signed by Australia, who will monitor and ensure that imported products are safe from potential health risks, whether these be “potential” or scientifically proven?
Considering the history of DDT, dieldren, asbestos and radioactive materials as health risks, should we take a cautious approach to all materials identified as potential carcinogens or generators of health risks?