|Occupational Health and Safety
Operational 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
- Lung cancer
"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:
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
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
- 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.
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 non-
smoker 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
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
- Pretreatment 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
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
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
- Strictly control exposure to carcinogenic substances that cannot be replaced
Source: CAW Health, Safety & Environment Department