Occupational Lung Diseases OCCUPATIONAL HEALTH AND SAFETY OCCUPATIONAL LUNG DISEASES The Major Types of Occupational Lung Diseases: Pneumoconioses, diseases caused by dust in the lungs Hypersensitivity diseases caused by allergic reactions in the lung to workplace contaminants Occupational bronchitis Emphysema Lung cancer 1. Pneumoconioses "Pneumoconiosis" is Greek for "dust in the lungs". This group of diseases, recognized over 2,000 years ago, affects workers who are exposed to dusts. Specific types of pneumoconioses include the following: a) Silicosis Silicosis is caused by the inhalation of crystalline silica dust. Mine and mill workers are at risk of direct exposure to crystalline silica, as are stonemasons and those involved in sandblasting. Furthermore, silica is used in foundry operations, in the making of pottery, bricks, glass and tile, in abrasive soaps and polishes, in some kinds of filters and in some kinds of sweeping comlpounds, so workers in many other occupations are exposed as well. Chronic Silicosis - affects workers who inhale small amounts of crystalline silica over 10 to 20 years. Those affected develop small nodules in their lungs. At first, there are no symptoms except possibly some shortness of breath during exercise. Complicated Silicosis - develops in 20 to 30 percent of chronic silicosis sufferers. This may happen even if exposure of the worker to the silica stops. In complicated silicosis the little nodules in the lungs become larger and join together into a large fibrosis (scar tissue), which spreads through the lungs. The function of the lungs is reduced, and heart disease related to lung disease often occurs as well. Symptoms include breathlessness, weakness, chest pain, cough and excess sputum. The end result is death due to heart failure.
Acute Silicosis - affects workers who are exposed to large amounts of crystalline silica over several months, e.g. those involved in sandblasting, tunneling, rock drilling and production of finely-ground silica. Early symptoms are difficulty breathing, weight loss, fever and cough. This disease progresses quickly and is usually not curable, leading to severe disability and death within five years. Dust control - wetting-down of surfaces in mines Ventilation Personal breathing apparatus in high-exposure conditions b) Coal Workers' Pneumoconiosis ("Black Lung") This disease is sometimes called "black lung" because autopsies reveal that the victim's lungs are full of black coal dust. About 10 to 30 percent of coal miners are affected. The frequency and severity of this disease vary from mine to mine, depending on the amount of dust in the air, the size of the dust particles, adequacy of ventilation and dust control, the types of machinery used, mining technique, and the type of rock around the coal seam. It appears to be more common in those mining hard coal (anthracite) rather than soft coal (bitumous coal). Simple Coal Workers' Pneumoconiosis - is common in workers who continually inhale coal dust. The dust builds up in the lungs and shows up in chest x-rays, but does not appear to cause any health problems, unless come other kind of lung disease is present. Complicated Coal Workers' Pneumoconiosis or Progressive Massive Fibrosis - occurs in 3 percent of those with simple coal workers' pneumoconiosis. In this disease, stiff, useless fibrotic tissue spreads through the lungs. Victims may die of respiratory failure, heart disease or infection. This disease often affects miners with heavy deposits of coal dust in their lungs, however it sometimes occurs in those with less dust in their lungs. It can also stop progressing, for unknown reasons. Dust Control Ventilation c) Asbestos-Related Lung Disease There are several diseases caused by asbestos. Their occurrence depends on the amount of asbestos fibres inhaled and the specific type of asbestos in the ore. Affected workers include asbestos miners and processors, construction and renovation workers exposed to asbestos insulation on pipes and inside walls and ceilings, and automotive mechanics and components makers exposed to asbestos in brake pads. Asbestosis - is lung fibrosis caused by asbestos. It starts with the body's attempt to protect itself from asbestos fibres stuck in the lungs, by forming tissue around the fibres. After 10 or 20 years of inhaling asbestos (4 or 5 if exposure is heavy) too much damage is done and lung fibrosis begins. The symptoms are coughing, sputum production, weight loss and breathlessness. Death usually occurs within 15 years after the symptoms
develop. The likelihood of developing asbestosis depends on the total amount of asbestos dust inhaled. Lung Cancer - causes 20 to 25 percent of deaths of workers heavily exposed to asbestos. Cigarette smoking greatly increases the ability of asbestos to cause cancer. An asbestos worker who smokes has 90 times the risk of getting lung cancer as does a nonsmoker who never worked with asbestos. Mesothelioma - is a cancer of the chest lining (Pleura). It is more frequent among workers exposed to crocodilite asbestos fibres. Due to their straight shape, crocodilite fibres appear to be able to pierce the lungs and lodge in lining of the rib cage where they cause cancer. The amount of exposure does not seem to matter. Mesothelioma had occurred in people living near asbestos processing operations and in the spouses of asbestos workers, whose partners inadvertently bring asbestos fibres home with them on their clothes, skin, hair, lunch boxes etc. Other Cancers - affect asbestos workers more frequently than most people, e.g. cancer of the esophagus, stomach and intestines. These are probably due to swallowing asbestos fibres coughed-up in mucus from the lungs. Dust control tight control on the use of asbestos use of substitute materials wherever possible d) Byssinosis Byssinosis occurs most often in those who work with raw cotton but also can affect those working with raw flax and hemp. Some unidentified natural plant material causes pneumoconiosis and an allergic reaction that eventually becomes permanent, and may develop into chronic bronchitis and emphysema. Dust control pre-treatment of plant material e) Other Types of Dust that may cause Pneumoconiosis Aluminum - In factories where explosives, fireworks, alumina abrasives (e.g. corundum) are made, pure, fine powder and aluminum oxide fumes may be inhaled. This is usually not harmful, but fibrosis can occur if particles of a specific size are inhaled. Beryllium - Workers may be chronically exposed to beryllium in facilities where it is extracted from ore. Amongst several diseases (including lung, liver and gall bladder cancers) it causes berylliosis, with symptoms of difficulty breathing, lung fibrosis over 10 to 20 years exposure and ultimately heart disease secondary to lung dysfunction. Berylliosis may be a hypersensitivity reaction.
Carbon Black and Graphite - can produce coal workers' pneumoconiosis if their inhalation is prolonged. Fuller's Earth - is an absorbent clay material used in foundries and oil refineries. It can cause a relatively harmless pneumoconiosis although there have been some reports of massive fibrosis. Kaolin - a fine silicate used in pharmaceuticals, ceramics, paint and papermaking rarely causes pneumoconiosis, but of those few who do contract it, massive fibrosis frequently develops. Mica - is mined and is used to make electrical and circuit board components, and is used in making furnaces. It can produce pneumoconiosis and a few incidents of fibrosis have been reported. Talc - may be inhaled in those mining and milling soapstone and by workers in several industries including cosmetics, rubber, asphalt, paint and pottery. It causes pneumoconiosis and those exposed to it have a high incidence of lung cancer, which may be due to contamination of the talc with asbestos. Cobalt and Tungsten Carbide - Workers processing tungsten carbide alloy may contract a hare-metal disease involving pneumoconiosis and an allergic obstructive lung disease. This may be due to cobalt, used as a binding agent when the tungsten and carbon are fused. 2. Hypersensitivity Diseases Occupational hypersensitivity diseases are allergic and asthmatic reactions that occur as a result of exposure to substances in the workplace. These reactions can occur in the large air passages of the lungs (the bronchi), the small passages (bronchioles) or the small sacs at the ends of the passages, where the blood picks up oxygen and releases carbon dioxide (the alveoli). The smaller the dust particles, the farther down they travel within the lung passages. a) Occupational Asthma Some people are genetically predisposed to have allergies, and these people are more likely to get occupational asthma. However some substances can sensitize people who do not naturally tend to get allergies, and set off occupational asthma. Examples are detergent enzymes, cereal, grain and wood dusts, plant fibres, insects, fungi, metals (chromium, nickel, vanadium, cobalt, stainless steel and platinum salts), formaldehyde, isocyanates, some pesticides and metalworking fluids. Asthma is a form of allergic reaction. The substance that sets the reaction off is referred to as an antigen. When an antigen enters the body of an allergic or sensitized worker, the body's immune system responds by producing substances which in turn cause the lung's airways to constrict. The symptoms of asthma are coughing, wheezing, shortness
of breath and feelings of constriction or strangulation in the throat and upper chest. Inflammation of the eyes (conjunctivitis) or nasal passages (rhinitis) may also accompany occupational asthma. In some people, a severe asthma attach can be fatal. At first, an occupational asthma sufferer becomes ill only when using a specific substance or when standing in a particular area of the workplace. Once the worker's exposure to the antigen stops, e.g. when the substance is not being used or when leaving the work area or the plant, the symptoms go away. However, if exposure to the antigen keeps happening and the asthma is not treated, chronic obstructive lung disease may result. If the worker experiences frequent asthma attacks at work, other things may end up triggering attacks, e.g. house dust, cigarette smoke, cold air, tiredness and coughing. Avoid the antigen (the substance that causes the asthma attack) eliminate the antigen from workplace air b) Hypersensitivity Pneumonitis (Allergic Alveolitis) Hypersensitivity pneumonitis is an allergic lung reaction caused by inhaling microorganisms such as mould (fungus), spores, yeast and bacteria as well as by "foreign" animal proteins such as those in animal hair, skin (e.g. dandruff) and milk (e.g. cheese and milk power). Mould can get into the lungs attached to particles of dust from wood, grain, animal hair, feathers, bird droppings, mushrooms and even spices and coffee beans. Microorganisms growing in metalworking fluids, air conditioning systems, ventilation systems and humidifiers can also cause hypersensitivity pneumonitis. The offending substances act as antigens, setting off an allergic reaction in the lungs. Symptoms of this disease occur a few hours after exposure to the antigen, and include tiredness, shortness of breath, dry cough, fever and chills. These symptoms may last for several days, and can be serious enough to require hospitalization. If the symptoms are mild, the worker may not notice that anything is wrong, but if exposure continues the inflammation of the lung's alveoli may progress to fibrosis. Hypersensitivity pneumonitis attacks can be treated with steroids and some other drugs, although they may not help very much. Bronchodilators (asthma "puffers") and antihistamines are no good at all. Recovery may take more than a month and there still may be some residual lung damage. If misdiagnosed and left untreated, this disease can be life-threatening. Avoid the antigen eliminate the antigen from workplace air eliminate the conditions that allow the fungi to grow personal breathing protection 3. Occupational Bronchitis Bronchitis is the response of the lungs to constant irritation, e.g. from cigarette smoke, air pollution, dust, irritant vapours and gases. Its symptoms are a persistent cough,
overproduction of mucus in the lungs (sputum) and reduced lung function. Workplace chemicals can irritate the lungs and may cause or contribute to the onset of bronchitis. Adequate local ventilation personal breathing protection 4. Emphysema Emphysema is a disease of the alveoli, the microscopic sacs at the very end of the air passages, where the blood picks up oxygen from the air and releases carbon dioxide. Chemical agents -- usually cigarette smoke but sometimes others including nitrogen dioxide and possibly cadmium -- damage the thin walls of the alveoli. The alveolar walls become less flexible and lose some of their ability to let oxygen and carbon dioxide pass through.. Eventually the alveolar walls break down and the alveoli join together to form larger air spaces. The large spaces are far less useful at transferring gases to and from the blood, and as a result less oxygen gets into the body when breathing. Symptoms include constant shortness of breath, gasping and wheezing. Emphysema is irreversible. 5. Occupational Lung Cancer It has been estimated that cancer-causing substances in the workplace cause 15 percent of lung cancers in men and 5 percent in women. However, it is very important to be aware that cigarettes are the most significant cause of lung cancer, and that a worker's risk of getting cancer from inhaling carcinogens at work is increased greatly by cigarette smoking. Restaurant and bar workers exposed to second-hand tobacco smoke are also at risk. Lung cancer cannot be cured. Workers who handle or are exposed to certain materials have a higher than average risk of getting lung cancer, i.e.: acrylonitrile, arsenic, asbestos, beryllium, bis-chloromethyl ether, chloromethyl methyl ether, cadmium, chromium, chromates, coal carbonization products, coal tar, coal tar pitch volatiles, ionizing radiation (including x-rays), metalworking fluids, mustard gas, nickel dust and fumes, petroleum, radium, tobacco smoke, uranium and vinyl chloride. For information about asbestos and cancer, please refer to section 1(c) above on asbestos related lung diseases. Do not start smoking, if you smoke, give it up ban smoking in your workplace replace carcinogenic (cancer-causing) or potentially carcinogenic substances used in the workplace with safer materials wherever possible strictly control exposure to carcinogenic substances that cannot be replaced