Cancer - what causes it?

Cancer can be caused by a number of chemicals, groups of chemicals, industries or industrial processes. Some chemicals are naturally found in foods and others are used for medicinal purposes. Some viruses can also cause cancer.The scientific consensus is that on average, 8% of cancer deaths are work-related. For some, like bladder and lung cancer, the figure is even well above 10%.

The International Labour Organisation (ILO) estimates the human toll at over 600,000 deaths a year – one death every 52 seconds. The ILO calculates that approximately 13% of all cancers in developed countries are the result of preventable, predictable workplace exposure. Today, more people face a workplace cancer risk than at any other time in history. According to international unions, the cancers are due in large part to the almost 100,000 synthetic chemicals that have been introduced into workplaces, resulting in worker exposure over the last century. Of all these substances, asbestos is fingered as 'the world's biggest ever industrial killer', as it is responsible for 100,000 deaths each year, a toll that could eventually amount to 10 million deaths worldwide.

Australian researchers, Dr Tim Driscoll, senior lecturer at the University's School of Public Health and Dr Lin Fritschi from Queensland Cancer, found in a 2006 study that one in ten male workers and one in 50 female workers developed cancer every year due to workplace exposure to carcinogens. See also article in the Sydney Morning Herald, October 2007: Workplace cancer a hidden toll

Occupational causes of cancer

Cancer	Examples of principal carcinogenic occupational exposures
Lung cancer	Asbestos; silica; nickel; indoor radon; diesel fumes; wood dust; environmental tobacco smoke (ETS) at the workplace; production and refining of: arsenic, beryllium, cadmium, aluminium and chromium; mining of uranium; copper smelting; iron and steel founding; vineyard workers; roofers; asphalt workers; painters; welders (see these articles: - Occupation as a cause of lung cancer on the verywellhealth website - Lung cancer is a leading cause of death on the Queensland government website)
Bladder cancer	Diesel fumes; 2-naphtylamine; benzidine; 4-aminobipheyl; manufacturing of: magenta, auramine, p-chloro-o-toluidine, pigment chromate, and dyes; sythetic latex production; tyre curing; calendar operatives; reclaim; cable makers; gas-retort workers; painters
Mesothelioma	Asbestos
Leukaemia	External ionizing radiation; benzene; ethylene oxide; rubber industry; boot and shoe manufacturing and repair
Laryngeal cancer	Sulfuric acid; mineral oils and asbestos; pickling operations
Skin cancer	Intensive solar radiation; coal-tar pitches; coal tar; shale oils; arsenic; mineral oils; polycyclic-aromatic hydrocarbons (PAH); production of coke; vineyard workers; fishermen
Sinonasal and nasopharyngeal cancer	Wood dust; nickel compounds; hexavalent chromium; boot and shoe manufacturing and repair; manufacturing of isopopanol using strong acid process; furniture and cabinet making; carpenters; formaldehyde
Kidney cancer	Coke production
Liver cancer	Vinyl chloride; occupational infections with hepatitis B and C; health care workers

(Table from Issue 11 - 2006, Global Occupational Health Network Newsletter {WHO])

The World Health Organisation, International Agency for Research on Cancer (IARC) regularly updates its monographs which list these according to the following catergories:

Group 1: Chemicals, groups of chemicals, industries or industrial processes for which there is sufficient evidence of carcinogenicity in humans.
Group 2A: Probably carcinogenic to humans.
Group 2B: Possibly carcinogenic to humans.
Group 3: Not classifiable as to its carcinogenicity in to humans.
Group 4: Probably not carcinogenic to humans.

In October 2007 scientists met at IARC to consider the carcinogenicity of painting, shiftwork and firefighting. Their conclusions, which have now been reflected in the IARC classifications:

Painting: "there is sufficient evidence in humans that occupational exposure as a painter causes cancers of the lung and urinary bladder." In addition, there is also limited evidence that painting is associated with childhood leukaemia. Overall, occupational exposure as a painter is carcinogenic to humans - Group 1
Shiftwork: on the basis of "limited evidence in humans for the carcinogenicity of shiftwork that involves nightwork, and sufficient evidence in experimental animals for the carcinogencity of light during the daily dark period (night)", shift-work that involves circadian disruption is probably carcinogenic to humans - Group 2A Note that there is increasing evidence that this is indeed the case.
Firefighting: on the basis of "limited evidence of carcinogenicity in humans", occupational exposure as a firefighter is possibly carcinogenic to humans - Group 2B

June 2012: IARC declared Diesel fumes a Group 1 carcinogen.

Outdoor air pollution - on October 17, 2013 IARC announced the classification of outdoor air pollution as a human carcinogen (Group 1). Although the composition of air pollution and exposure levels vary widely from place to place, IARC says its assessment is applicable worldwide and notes that exposures in rapidly industrializing countries with large populations have increased significantly in recent years. According to the IARC review of the latest scientific studies, exposure to air pollution increases the risk for lung cancer and for bladder cancer. IARC also evaluated particulate matter, a major component of air pollution, and concluded that it too is a human carcinogen.

IARC notes that in 2010 – the most recent annual data available – approximately 223,000 deaths worldwide resulted from lung cancer prompted by air pollution. Meanwhile air pollution-related respiratory and cardiovascular diseases continue to decrease life expectancy worldwide.
This is the first time outdoor air pollution has been classified as a cause of cancer.
IARC Press Release [pdf]

Over 40% of Australian workers exposed to carcinogens

In late 2013, Australian researchers from the universities of WA, Monash and Sydney, published the results of their Australian Work Exposures Study (AWES), which investigated the prevalence of occupational exposure to carcinogens. A random sample of men and women (between 18 and 65 yrs old), in paid employment, were invited to participate in a telephone interview collecting information about their current job and various demographic factors. Responses were obtained from 5023 workers.

Of these, 1879 respondents (37.6%) were assessed as being exposed to at least one occupational carcinogen in their current job. Extrapolation of these figures to the Australian working population suggested 3.6 million (40.3%) current workers could be exposed to carcinogens in their workplace. Exposure prevalence was highest among farmers, drivers, miners and transport workers, as well as men and those residing in regional areas.

Renee N Carey, Timothy R Driscoll, Susan Peters, Deborah C Glass, Alison Reid, Geza Benke, Lin Fritschi Estimated prevalence of exposure to occupational carcinogens in Australia (2011–2012) [abstract] Occup Environ Med doi:10.1136/oemed-2013-101651

Workers with cancer

Almost one in three Australians are or will be directly affected by cancer - many of them workers. Being diagnosed with cancer causes fear and affects every aspect of a person's life, including their ability to work. While many cancers can be cured, the tests and treatments, such as surgery, chemotherapy and radiotherapy, may mean time spent in hospital and recuperating. In addition, the symptoms of cancer or the side effects of treatment may affect a person's ability to work as effectively as before their illness.

Some people may wish to continue to work, if they can, or return to work as soon as possible. Others may decide to retire early or may be unable to continue to work in any capacity.

Workplaces should consider developing a cancer and working policy. This is something that either health and safety representatives, and/or OHS committee could raise for consideration at their workplace. This policy could apply equally to any employee with a critical illness and be helpful in encouraging an open environment where workers who are affected can raise concerns and not be stigmatised. A very useful publication has been developed by a group of UK organisations: Cancer and Working - Guidelines for Employers, HR and Line Managers [pdf]. The publication includes a template policy and provides useful and practical advice for workplaces.

(Acknowledgement: This material in this section has been taken - with thanks - from the guidelines which were produced as a collaboration between UK groups Cancerbackup; the Chartered Institute of Personnel and Development [CIPD] and the Working with Cancer [WwC] group)

Cancer - what causes it?

Over 40% of Australian workers exposed to carcinogens

Workers with cancer

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