Pneumoconiosis is a term that is used to refer to the group of lung diseases caused by the inhalation of the dust and mineral particles. It is also referred to as an occupational or restrictive lung disease. Occupational lung diseases are caused due to the exposure of harmful substances, dust or gases at the work place. The reason for this is that it is caused by the inhalation of the dust or mineral particles by the workers who usually work in the industry that is mineral related and is at high risk such as coal mines (Pneumoconiosis, 2013). Coal dust, Asbestos, crystalline silica, some forms of silicone dioxide and barium are some of the substances that are known to cause the lung diseases.
In Pneumoconiosis, the dust or chemical particles at first cause an inflammation in the lungs which gradually cause the temporary damage to certain areas of the lungs. As the time passes, these damaged areas take a form of tough fibrous tissue deposits in the lungs. At this stage, it is referred to as Fibrosis. This cause stiffening in the lungs, making it difficult for the lungs to function normally (Pneumoconiosis, 2013). There are many different types of Pneumoconiosis depending on the type of substance inhaled by the individual. But some of the primary Pneumoconiosis are asbestosis, silicosis, and coal workers’ pneumoconiosis. These three types are caused by the inhalation of the related chemical and coal particles as indicated by their names. It takes years for Pneumoconiosis to develop and manifest itself. There are other forms of Pneumoconiosis that are caused due to inhalation of dust particles having aluminium, antimony, barium, graphite, iron, kaolin, mica, talc, etc in them. There is also another form of Pneumoconiosis referred to as ‘mixed- dust pneumoconiosis’ (Pneumoconiosis, 2013).
The research question which I shall explore in this paper is that whether coal miner’s pneumoconiosis, lead towards the development of lung cancer or not?
Progression of Pneumoconiosis
Normally, the lung tissues are elastic in nature, allowing comfortable expansion and contraction while breathing. In case of Pneumoconiosis, the lungs develop fibrous tissues, the condition which is called fibrosis. Fibrosis cause stiffening in lung tissues which causes restriction in their expansion. The person who is affected by fibrosis develop serious breathing problems and sometimes even cancer which eventually cause death. So it is very important to diagnose the condition as early as possible to prevent further damage to the lungs.
Discussion on Coal Miner’s Pneumoconiosis
· History and efforts for its prevention
The dangers of coal Miner’s Pneumoconiosis were not not fully understood until the 1950s. At that time it was viewed that silicosis is more serious and severe and coal dust is not. The United Mine workers of America, the miners’ association realized that with the rapid mechanization of the coal mining industry and the use of drilling method would cause lots of coal dust. Due to mechanization they were able to get higher productivity and wages, so they decided not to raise any issues related to the disease caused by dust. The black dust disease was later recognized as a lung disease as they realized the importance financial funds for the miner’s who were disabled. In 1969, Federal Coal Mine Health and Safety Act was created by the U.S. Congress which set up certain standards for the reduction of dust and also founded the Black Lung Disability Trust. This Act helped the disabled mine workers to get adequate compensation. Another important clause of this act was the ‘rate retention’. According to this the affected workers with progressive disease of the lungs, were allowed to shift to the jobs which offer less exposure to the dust without a reduction in their pay, position and other benefits. According to one estimate, a miner who spent almost 25 years in the coal mines underground are at 5-10 % risk of developing the disease (Alan,1998).
· Studies conducted on Coal Miner’s Pneumoconiosis
National Coal Board (NCB) founded the Institute of Occupational Medicine (IOM) in 1969. Dr. John Regan was its founder who sets up the Pneumoconiosis Field Research (PFR). The objective behind its foundation was to conduct studies on what is the extent and what types of coal dust becomes a cause of pneumoconiosis. It also researched about what concentration of airborne dust particles should be maintained to save the miners from the disability caused due to inhalation of those particles. In 1970, the first research results were published in the scientific journal ‘Natural’ by PFR (Jacobsen, Rae et.al, 1971). The research gave recommendations for the development of standards for the stringent airborne dust particles in the coal mines of British. It later on forms the basis of standard for dust particles around the world.
The studies conducted by IOM have developed a positive relationship between the decrease in the functioning of lung and the concentration of the dust particles in the lungs of coal miner’s.
In a study a review was conducted to find , the effect of exposure to the coal mine dust and crystalline silica which results in pneumoconiosis which in turn cause initiation and progression of pulmonary fibrosis. The review presented the characteristics of the simple and complicated type of Coal worker’s pneumoconiosis along with the pathology of acute and chronic silicosis (Castranova & Vallyathan, 2000). The results summarized the investigations done on humans and animals. The etiology of coal worker’s pneumoconiosis and silicosis supported the four basic mechanisms;
· The direct exposure or toxicity of coal dust or silica cause damage to the lung cells, released lipases and proteases and eventually caused scarring in the lungs
· The pulmonary phagocytes results in the activation of oxidant production which overtakes the antioxidant defences and causes preoxidation of lipids, protein nitrosation, injury to cells and scarring in the lungs.
· Alveolar macrophages and epithelial cells activate mediator release. This recruits polymorphonuclear leukocytes and macrophages, which results in the production of proinflammatory cytokines, some reactive type of species, further injury to the lungs and scarring in the lungs.
· Alveolar macrophages and epithelial cells, secrete growth factors which stimulate the fibroblast proliferation and eventually cause scarring in the lungs (Castranova & Vallaythan,2000).
The data obtained from the coal workers supported the results of the study .
A study was undertaken in 563 patients with non asbestos pneumoconiosis, to evaluate the incidence of Diffuse interstitial Fibrosis (DIF) through a CT scan and how much it contributes towards lung cancer ( Katabami, Dosaka-Akita, Honma, et.al, 2000). The results of the study showed that patients who had pneumoconisosis with DIF had increasingly high concurrence rate as compared to the patients who had pneumoconiosis without DIF. The results suggested a positive causal relationship between the pneumoconiosis and the incidence of lung cancer in the patients with DIF- type of Pneumoconisosis.
A pilot study conducted on the selected cohort of 334 dutch coal miner’s who had coal worker’s pneumoconiosis(CWP). The study was followed from 1956 till 1983. The purpose of the study was to investigate whether prolonged dust exposure of coal miner’s to coal mine dust increase the risk of cancer in them (Meijers, Swaen, et.al,1991). During the period of study, 165 miner’s died out of these the cause of death of 162 miner’s were traced. The expected mortality rate due to the cancer of the stomach, small intestine and the non-malignant respiratory disease in the cohort was significantly higher as compared to the general Dutch male population.
A research study conducted by Goldman (1965) to investigate the mortality of the coal-miner’s due to the lung carcinoma. For the study, comprehensive investigations were done on the mortality of the National Coal board Miner’s and ex-miner’s, a result of the comprehensive survey conducted in the Welsh mining community related to the respiratory disease and the results of the comparative mortality study in Welsh mining and non-mining towns due to lung cancer. The results of these investigations along with the previously published data on the subject were reviewed. The results showed that in Great Britain the rate of death of coal miner’s due to lung cancer was significantly low as compared to the national mortality rate of men of the same age. There has been an evidences that the rate of death among coal miner’s from lung cancer is lowest who have a higher exposure to the coal-dust.
A 16-year of follow –up study was conducted on 16, 628 coal miner’s. The results of the study showed very high mortality rate among the cigarette smoking coal miner’s rather than the nonsmokers. The incidence of lung cancer was less in the coal miner’s with pneumoconiosis (Jacobsen,1979).
Another study was conducted on the coal-miner’s in South Wales with pneumoconiosis to study the incidence of lung cancer (James,1955). The results showed that out of 1,827 coal miners, 967 had developed simple pneumoconiosis and 860 had developed massive fibrosis. The rate of lung cancer that was found in necroscopy was 3.3% in 1827 South Wales coal miners and the rate was 5.4 % in 1531 Soth wales non-miners population. The physiology of lung cancer in both the coal miner’s and non-miners population was same with respect to age, tumour and metastases distribution.
Pneumoconiosis in the 21st Century
The first efforts towards the study of coal miner’s pneumoconiosis started in 1966 by Doctors I.E. Buff, Harvey Wells, and Donald Rasmussen. Earl Stafford was the first miner who helped them to conduct their first experiments on coal miner’s diseases. The doctors together continued their efforts towards providing help and developing preventive measures for the elimination of the diseases caused by the coal mine dust.
The passing of the law of Federal Coal Mine Health and Safety Act of 1969 and its implementation caused a significant decrease in the percentage of the coal miners who suffered from the black lung disease. But in the recent years it has again started increasing. According to the reports of the National Institute for Occupational Safety and Health (NIOSH), during 2005-2006 almost 9% of coal miners of age 25 or more showed positive tests of black lung disease as compared to the 4% in late 1990s ( Coal mine dust exposures and associated health outcomes, 2011).
Some new findings also suggest that surface coal miners can also be at the risk of developing Coal workers pneumoconiosis, as they form the 48% of the workforce.
In 2010-2011, a data of the chest X-rays of almost more than 2000 coal mine workers from 16 US states was examined by Coal Workers' Health Surveillance Program of NIOSH. The analysis of data showed that the 2% of surface coal miners who had one or more year of mining experience developed the Coal Worker’s Pneumoconiosis(Laney, Wolfe, et.al, 2012).
A Mobile Health Screening Program has been started by the National Institute of Occupational safety and Health (NIOSH) together with Mine Safety and Health Administration (MSHA). The purpose of this mobile unit is to travel across U.S. mining regions. The miners are encouraged to participate in the program as they receive an evaluation of their health once in every five years without any cost. The X-rays of chest can detect the possible development of CW, often before the appearance of any symptoms in miners.
The analysis of the various studies indicates that the lung cancer is not primarily caused by pneumoconiosis in coal mine workers. The pneumoconiosis is itself a disease causing damage to the lung tissues and in severe cases fibrosis. The decrease in the immunity of the patient due to pneumoconiosis can become a cause of the development of certain other types of carcinomas or cancers but there is no strong relation found between the development of lung cancer and pneumoconiosis. Even the mortality rate of coal mine workers with pneumoconiosis was found significantly low as compared to the general population who died due to lung cancer. Pneumoconiosis do cause damage to the lungs but not necessarily identified as a cause of the development of lung cancer. There are other kinds of pneumoconiosis which can said to be responsible for lung cancer but it is not essentially a cause of lung cancer in coal mine workers with pneumoconiosis. There are other factors such as rate of cigarette smoking in the coal mine workers which can contribute towards its onset.
Government has made efforts and passed certain acts and laws for the prevention of pneumoconiosis in the coal mine workers. These institutions conduct studies and provide help to the coal mine workers in early detection and prevention of pneumoconiosis.
The only way in which the CWP can be prevented is avoiding the inhalation of coal dust. There has been certain standards that are set up for coal mine workers by the Occupational Safety & Health Administration (OSHA) (part of the U.S. Department of Labor). The standards formed to provide guidelines for the protective requirements that are essential for the individuals who works around carbon, graphite or man made carbon mines and industries. They are required to wear safety masks and follow the rules set by the standards. These standards provide safety and prevention from the coal dust and other related mineral particles.
Some of the recommendations for its prevention are;
· In case of contact of the workers with the coal dust , the affected area should be immediately washed with water and soap.
· If the clothing of the workers gets contaminated with the dust of the coal, it should be immediately removed. Its the responsibility of the employer to provide an appropriate and safe system for the removal of dust from the clothes. People who do the laundry should also be made aware of the dangers associated with the coal dust so they can take appropriate measures.
· The employers at the coal mines or where carbon related dust particles are present should wash their hands, face , arms with soap and water before doing any other thing such as eating, drinking, applying cosmetics, taking any medication, visiting the toilet etc.
· The workers who work near or at the places where there is coal dust , should not eat, drink, use any tobacco items,or take medication in that area.
The companies or industries should make efforts to enforce the standards and should provide their employees with the facility of regular checkups for any traces of contamination of the lungs by the carbon dust. In case pneumoconiosis is detected in any worker, he should be immediately removed from the high dust concentration areas and allowed to work in some other department.
Concentrated efforts by the companies and the government can help in the prevention and decrease in the rate of pneumoconiosis.
Castranova,V. & Vallaythan,V.(2000). Silicosis and coal workers' pneumoconiosis. Environ Health Perspect.August; 108(Suppl 4): 675–684.
Coal Mine Dust Exposure and Associated Health Outcomes. (2011). Current Intelligence Bulletin. Retrieved on 9 May 2013 from http://www.cdc.gov/niosh/docs/2011-172/pdfs/2011-172.pdf
Enhanced Coal Workers' Health Surveillance Program.(2013). National Institute for Occupational Safety and Health. Retrieved on 9th May 2013 from http://www.cdc.gov/niosh/topics/surveillance/ORDS/ecwhsp.html
Goldman,K.P.(1965). Mortality of the Coal-miners from Carcinoma of the lung cancer. British Journal of Industrial Medicine, Vol. 22, No. 1, pp.72-77.
Jacobsen,M. (1979). Lung cancer and coal workers' pneumoconiosis. Br Med J. July 21; 2(6183): 208.