worker may be exposed to five types of hazards, depending upon his/her
India, the most common physical hazard is heat. The direct effects
of heat exposure are burns, heat exhaustion, heat stroke and heat
cramps; the indirect effects are decreased efficiency, increased
fatigue and enhanced accident rates. Many industries have local
“hot spots” – ovens and furnaces, which radiate heat. Radiant heat
is the main problem in foundry, glass and steel industries, while
heat stagnation is the principal problem in jute and cotton textile.
High temperatures are also found in mines. Physical work under such
conditions is very stressful and impairs the health and efficiency
of the workers. For gainful work involving sustained and repeated
effort, a reasonable temperature must be maintained in each work
hazards associated with cold work are chilblains, erythrocyanosis,
immersion foot, and frostbite as a result of cutaneous vasoconstriction.
General hypothermia is not unusual.
workers may be exposed to the risk of poor illumination or excessive
brightness. The acute effects of poor illumination are eye strain,
headache, eye pain, lachrymation, congestion around the cornea and
eye fatigue. The chronic effects on health include “miners’s nystagmus”.
Exposure to excessive brightness or “glare” is associated with discomfort,
annoyance and visual fatigue. Intense direct glare may also result
in blurring of vision and lead to accidents. There should be sufficient
and suitable lighting, natural or artificial, wherever persons are
is a health hazard in many industries. The effects of noise are
of two types:
Auditory effects - which consist of temporary or permanent
Non-auditory effects – which consist of nervousness, fatigue,
interference with communication by speech, decreased efficiency
The degree of injury from exposure to noise depends upon a number
of factors such as intensity and frequency range, duration of exposure
and individual susceptibility.
especially in the frequency range 10 to 500 Hz. May be encountered
in work with pneumatic tools such as drills and hammers. Vibration
usually affects the hands and arms. After some months or years of
exposure, the fine blood vessels of the fingers may become increasingly
sensitive to spasm (white fingers). Exposure to vibration may also
produce injuries of the joints, of the hands, elbows and shoulders.
exposure to ultraviolet radiation occurs mainly in arc welding.
Such radiation occurs mainly affects the eyes, causing intense conjunctivitis
and keratitis (welder’s flash). Symptoms are redness of the eyes
and pain, these usually disappear in a few days with no permanent
effect on the vision or on the deeper structures of the eye.
radiation is finding increasing application in medicine and industry,
e.g. x-rays and radio active isotopes. Important radio-isotopes
are cobalt60 and phosphorus32. Certain tissues such as bonemarrow
are more sensitive than others and from a genetic standpoint, there
are special hazards when the gonads are exposed. The radiation hazards
comprise genetic changes, malformation, cancer, leukaemia, depilation,
ulceration, sterility and in extreme cases death. The International
Commission of Radiological Protection has set the maximum permissible
level of occupational exposure at 5 rem per year to the whole body.
is hardly any industry which does not make use of chemicals. The
chemical hazards are on the increase with the introduction of newer
and complex chemicals. Chemical agents act in three ways: local
action, inhalation and ingestion. The ill-effects produced depend
upon the duration of exposure, the quantum of exposure and individual
chemicals cause dermatitis, eczema, ulcers and even cancer by primary
irritant action; some cause dermatitis by an allergic action. Some
chemicals, particularly the aromatic nitro and amino compounds such
as TNT and aniline are absorbed through the skin and cause systemic
effects. Occupational dermatitis is a big problem in industry.
– Dusts are finely divided solid particles with size ranging from
0.1 to 150 microns. They are released into the atmosphere during
crushing, grinding, abrading, loading and unloading operations.
Dusts are produced in a number of industries – mines, foundry quarry,
pottery, textile, wood or stone working industries. Dust particles
larger than 10 microns settle down from the air rapidly, while the
smaller ones remain suspended indefinitely. Particles smaller than
5 microns are directly inhaled into the lungs and are retained there.
This fraction of the dust is called “respirable dust”, and is mainly
responsible for pneumoconiosis. Dusts have been classified into
inorganic and organic dusts; soluble and insoluble dusts. The inorganic
dusts are silica, mica, coal, asbestos dust, etc.; the organic dusts
are cotton, jute and the like. The soluble dusts dissolve slowly,
enter the systemic circulation and are eventually eliminated by
body metabolism. The insoluble dusts remain, more or less, permanently
in the lungs. They are mainly the cause of pneumoconiosis. The most
common dust diseases are silicosis and anthracosis
– Exposure to gases is a common hazard in industries. Gases are
sometimes classified as simple gases (e.g. oxygen, hydrogen), asphyxiating
gases (e.g. carbon monoxide, cyanide gas, sulphur dioxide, chlorine)
and anesthetic gases (e.g. chloroform, ether, trichlorethylene).
Carbon monoxide hazard is frequently reported in coal-gas manufacturing
plants and steel industry.
and their Compounds
– A large number of metals and their compounds are used throughout
industry. The chief mode of entry of some of them is by inhalation
as dust or fumes. The industrial physician should be aware of the
toxic effects of lead, antimony, arsenic, beryllium, cadmium, cobalt,
manganese, mercury, phosphorus, chromium, zinc and others. The ill-effects
depend upon the duration of exposure and the dose or concentration
of exposure. Unlike the pneumoconiosis, most chemical intoxications
respond favourably to cessation, exposure and medical treatment.
diseases may also result from ingestion of chemical substances such
as lead, mercury, arsenic, zinc, chromium, cadmium, phosphorus,
etc. Usually these substances are swallowed in minute amounts through
contaminated hands, food or cigarettes. Much of the ingested material
is excreted through faeces and only a small proportion may reach
the general blood circulation.
may be exposed to infective and parasitic agents at the place of
work. The occupational diseases in this category are brucellosis,
leptospirosis, anthrax, hydatidosis, psittacosis, tetanus, encephalitis,
fungal infections, schistosomiasis and a host of others. Persons
working among animal products (e.g. hair, wool, hides) and agricultural
workers are specially exposed to biological hazards.
mechanical hazards in industry centre round machinery, protruding
and moving parts and the like. About 10% of accidents in industry
are said to be due to mechanical causes.
psychosocial hazards arise from the workers’ failure to adapt to
an alien psychosocial environment. Frustration, lack of job satisfaction,
insecurity, poor human relationships, emotional tension are some
of the psychosocial factors which may undermine both physical and
mental health of the workers. The capacity to adapt to different
working environments is influenced by many factors such as education,
cultural background, family life, social habits and what the worker
expects from employment.
health effects can be classified in two main categories –
Psychological and behavioural changes – including hostility,
aggressiveness, anxiety, depression, tardiness, alcoholism, drug
abuse, sickness absenteeism
Psychosomatic illhealth – including fatigue, headache; pain
in the shoulders, neck and back; propensity to peptic ulcer, hypertension,
heart disease and rapid aging.
physical factors (heat, noise, poor lighting) play a major role
in adding to or precipitating mental disorders among workers. The
increasing stress on automation, electronic operations and nuclear
energy may introduce newer psychosocial health problems in industry.
Psychosocial hazards are there fore assuming more importance than
physical or chemical hazards.