1. OCCUPATION
AL
MEDICINE
AND
OCCUPATION
AL
DISEASES

2. OCCUPATIONAL MEDICINE
• Branch of medicine which is
devoted for the promotion and
protection of workers health.
• Early diagnosis and treatment
of diseases of occupational
origin, and rehabilitation of
disablement of workers.

3. Historical Background
• Paracelsus, 1493 – 1541.
• Bernardino Ramazzini,
1633 – 1714.
• Charles Turner Thackrah,1795 –
1833.
• Promulgation of Factory Act,
1819.
• Appointment of Certifying
Factory Surgeon, 1884.

4. Occupational Health Hazards
• Physical agents : Heat, Light,
Cold, Humidity, Air pressure,
Vibrations, Noise, E.M.F., Injurious
force, Dusts, Radiant energy.
• Chemical agents : Noxious
gasses, Aerosols, Corrosives,
Solvents, Metals and Metal fumes,
Insecticides and Herbicides.

5. • Biological agents : Bacteria's,
Viruses, Fungi, Molds and other
biological agents.
• Mechanical agents : badly
maintained machines, Lack of
protective devices .
• Social factors : Job security and
working conditions, work related
tensions and worries, family
pressures.

6. • Noise : Hearing impairment, hearing
loss.
• Light : headache, loss of
concentration and miners nystagmus.
• E.M.F.: Headache, sleep disturbances,
risk of blood and brain cancer.
• Radiant energy :a) Cosmic radiation :-
Cataract, skin cancer. b) U.V.
radiation :- Skin and bone cancer.
• Injurious force : injuries and
accidents.

7. • Ionising radiation : a) acute effects :-
Radiation burns, acute radiation
syndrome.
b) delayed effects :- Genetic mutations,
cancers, teratogenesis.
 Dusts : organic and inorganic :-
Respiratory diseases, Pneumoconioses.
 Chemical agents : Burns, Occupational
dermatoses and cancers.
 Biological agents : Various agent
specific diseases.
 Social factors : Nature of work and
working hours,
Jealousy in promotions, poor housing,
less pay, separation from family and lack
of job satisfaction.

8. Noise
Noise is often defined as “unwanted
sound”, but this definition is quite
subjective.
A better definition of noise is “wrong
sound, in the wrong place, and the
wrong time, leading to health
hazard”. Noise has become a very
important stress factor in the
environment of man and the term “Noise
Pollution” has been accepted.
Noise is also one of the most common
of all the occupational hazards.

9. Sources of noise – they are many
and varied.
These are automobiles, factories,
industries – woodcutters, textiles, primary
metals, petroleum and coal, chemicals,
printing and publishing, aircraft etc.
The domestic noises from the radios,
TV sets, vacuum cleaners, elevators etc.
add the quantum of noise in daily life.
Properties – noise has two important
properties – intensity or loudness, and
- frequency.

10. INTENSITY
Intensity or loudness depends
upon the amplitude of the
vibrations, which initiated the
noise. The intensity of noise is
measured in decibels (dB). When
we say that sound is 60 dB, it
means that it is 60 dB more intense
than the smallest distinguishable
noise. Normal conversation
produces a noise of 60-65 dB.

11. Acceptable noise levels (dB/A)
Acceptable noise levels (dB/A)
Residential: Bed room 25
Living room 40
Commercial: Office 35-45
Conference 40-45
Restaurants 40-60
Industrial:
Workshop 40-60
Laboratory 40-50
Educational: Class room 30-40
Library 35-40
Hospitals: Wards 20-35

12. Sound levels of some noises
Source of noise Sound Level (dB/A)
Wishper 10
Speech, 2-3 people 73
Speech on radio 80
Music on radio 85
Children shouting 79
Children crying 80
Vacuum cleaner 76
Piano 86
Jet take off 150

13. It has been observed that the human
ear responds in a non-uniform way to
different sound pressure levels, that is, it
responds not to the real loudness of a
sound, but to the perceived intensity.
A weighting curve A has been
constructed, which takes into account the
subjective effects of the sound. Sound
pressure levels are therefore expressed in
dB (A). This is in decibels conforming to
the weighting curve A and reflects the
perception of that sound emission by the
normal human ear.

14. Community noise levels
160 Mechanical damage
150
140 Threshold of pain
130
120 Motor car horn
110 Train passing station
100
90 Recommended maximum (85 dB)
80 Printing-press
70 Heavy street traffic
60 Normal conversation
50
40 Quiet library
30
20 Whispering
10

15. FREQUENCY
The frequency is denoted in
Hertz (Hz). One Hz is equal to one
wave per second. The human ear
can hear frequencies from about
20 to 20 000 Hz, but this range is
reduced by age and other
subjective factors. The range of
frequencies below 20 Hz are infra-
audible, and those above 20 000
Hz are ultra-sonic.

16. Measurement of noise
The basic instruments used in
studies on noise are:
1. Sound level meter, which
measures the intensity of sound in dB or
dB (A)
2. Octave-band frequency
analyzer, which measures the noise in
octave bands. The resulting plot shows
the “sound spectrum” and indicates the
characteristics of the noise, whether it
is mainly of high frequency, low
frequency or of variable frequency.

17. 3. Integrating sound level meter
and Noise dose meter or “dosimeter”
(for measuring mainly of industrial noise).
For measuring of non-steady noise
exposures, such as those that occur in
intermittent or impulse noise, an integrated
sound level meter is most convenient to use,
which measure simultaneously the
equivalent, peak and maximum sound levels.
The noise dose meter or “dosimeter”
is a form of integrating sound level meter
that can be worn in shirt pocket or attached
to the worker’s clothing. Data form the
dosimeter may be computerized or printed

18. Measuring procedures in
the workplace
There are two basic approaches to
measuring noise in the workplace:
• The exposure of each worker, worker
type or worker representative may be
measured. The noise dosimeter is the
preferable instrument for this purpose.
• Noise levels may be measured in various
areas, creating a noise map for the
determination of risk areas. In this case,
a sound level meter would be used to
take readings at regular points in a
coordinate network.

19. Effects of noise
exposure
Auditory effects
• Auditory fatigue – it appears in the 90 dB
region and greatest at 4000 Hz.
• Deafness or hearing loss – this is the most
serious pathological effect. When this occurs
as a result of occupation in industries, it is
called “occupational hearing loss”. Hearing
loss may be temporary or permanent. The
temporary one results from a specific
exposure to noise and disability disappears
after about 24 hours. Repeated or continuous
exposure to noise above 85-90 dB may result
in a permanent hearing loss.

20. Non – auditory effects
Annoyance – a primary
psychological aspect; neurotic
people, especially workers
occupationally exposed to high
noise become often irritated and
impatient and disrupt
production, which also reduces
the efficiency of work with
economic losses.

21. Non – auditory effects
Physiological changes – a
number of temporary psychological
changes occur in the human body as
a direct result of noise exposure.
These are: a rise in blood pressure, a
rise in intracranial pressure, an
increase in heart rate and breathing
and an increase in sweating, increase
in catecholamines production,
alteration in the functions of
gastrointestinal and endocrine
systems etc. General symptoms as
fatigue, nausea, visual disturbances
may also occur.

22. Control of noise
Careful planning of cities –
in planning cities, the following
measures should be taken to reduce
noise:
• Division of the cities into zones
with separation of areas concerned
with industry and transport and
separation of residential areas from
the main streets by means of wide
green belts. House fronts should lie
not less than 15 meters from the road
and the intervening space should be
thickly planted with trees and bushes.

23. Control of vehicles – heavy
vehicles should not be routed into narrow
streets; traffic on residential streets
should be reduced.
Improving of the acoustic
insulation of buildings – from the
acoustic standpoint, the best
arrangement is construction of detached
buildings than a single large building.
Installations that produce noise or
disturb the occupants within dwellings
should be prohibited. Buildings should be
sound-proof where necessary.

24. Control of industrial
noise – control of noise at
source is possible in
industries. The use of
written specifications to
define the requirements for
equipment, its installation,
and acceptance should be a
standard practice. Once the
equipment is installed and
excess noise identified,
there are:

25. - Engineering controls available.
Such are: replacement or
adjustment of machines,
lubrication of machine parts,
reducing noise by using sound
absorptive materials on walls
and ceilings in work areas, by
using sound barriers along the
transmission path or complete
enclosure of individual machines,
isolation of the operator by providing
a relatively soundproof booth.

26. - Personal hearing protection – it
is recommended for all workers who
are consistently exposed to noise
louder than 85 dB in the frequencies
above 150 Hz, and is performed by
use of hearing-protective devices.
Workers must be regularly rotated
from noisy areas to comparatively
quiet posts in factory. Periodical
audiogram check-ups are also
important for worker’s health
prevention. Workers have the right to
claim compensation if they have
suffered a hearing loss.

27. Vibration
Vibration is oscillatory motion.
Whole-body vibration occurs when
the body is supported on a surface
which is vibrating (e.g., when sitting on
a seat which vibrates, standing on a
vibrating floor or surface). Whole-body
vibration occurs in all forms of transport
and when working near some industrial
machinery – buldozers, excavators,
eorest machines, mine and quorry
equipment, concrete production
production etc.

28. Hand-transmitted vibration is
vibration that enters the body
through the hands. It is caused by
various processes in industry,
forestry, agriculture, mining, and
construction where vibrating tools or
workpieces are grasped or pushed by
the hands or fingers.
The main parameters of vibration
the health effects depend on are:

29. Magnitude
Oscillatory displacements of an object
involve a velocity in one direction and then
a velocity on the opposite direction. This
change of velocity means that the object is
constantly accelerating, first in one
direction and then in the opposite
direction. The magnitude of an oscillation
can be quantified by its displacement, its
velocity or its acceleration. The units of
acceleration are meters per second
(m/s2).

30. The magnitude of
vibration can be expressed
as the distance between the
extremities reached by the
motion (the peak-to-peak
value) or the distance from
some central point to the
maximum deviation (the
peak value), this is also
called amplitude.

31. Frequency
The frequency of vibration, which
is expressed in cycles per second
(Hz), affects the extent to which
vibration is transmitted to the
body (e.g. to the surface of a seat
or the handle of a vibratory tool),
the extent to which it is
transmitted through the body
(e.g. from the seat to the head),
and the effect of vibration in
the body.

32. The relation between the
displacement and the acceleration of a
motion are dependent on the frequency of
oscillation; a displacement of one mm
corresponds to a very low
acceleration at low frequencies but a
very high acceleration at high
frequencies.

33. The effects of whole-body
vibration are usually greatest at the
range from 0.5 to 100 Hz. For hand-
transmitted vibration, frequencies
as high as 1000 Hz or more may
have adverse health effects.
Frequencies below about 0.5 Hz can
cause motion sickness.

34. The frequency content of
vibration can be shown in spectra.
For many types of vibration the
spectra are complex, with some
motion occurring at all
frequencies. Nevertheless, there
are often peaks, which show the
frequencies at which most of
the vibration occurs.

35. Direction
Vibration may take
place in three directions –
x-axis (fore-and-aft), y-axis
(lateral) and z-axis
(vertical).
Vibration is usually
measured at the interface
between the body and the
vibration.

36. Duration
Human responses to vibration depend
on the total duration of vibration exposure.
Many occupational exposures are
intermittent, vary in magnitude from
moment to moment or contain occasional
shocks. The severity of such complex
motion can be accumulated in a manner
giving appropriate weight to short periods
of high magnitude vibration or low periods
of low magnitude vibration. Different
methods for calculating doses are
used.

37. Measurement and evaluation of
exposure
Vibration measurements are made to
provide assistance for the development of
new tools, to check these tools at
purchase, to verify maintenance
conditions, and to assess human exposure
to vibration at workplace.
Vibration-measuring equipment
generally consists of a transducer (usually
an accelerometer), an amplifying device
and amplitude indicator.

38. Whole-body vibration
should be measured at the
interfaces between the body
and the source of vibration. For
seated persons this involves the
placement of accelerometers on
the seat surface beneath the
ischial tuberosities of subject.
Vibration is sometimes
measured at the seat back or at
feet and hands.

39. The presence of other
adverse environmental factors,
especially sitting posture,
should be also be considered.
It is assumed that for health
effect estimation the total
exposure, rather than the
average exposure, is important,
and so a dose measure is
appropriate.

40. Hand-transmitted
vibration
Vibration measurements should be
made on the tool handle or workpiece
close to the surface of the hand(s) where
the vibration enters the body.
In several (and the Bulgarian)
standards hand-transmitted exposure is
assesses in terms of four-hour and eight-
hour energy-equivalent frequency-
weighted acceleration calculated by
means of equations.

41. Prevention
The prevention of injuries or disorders
caused by vibration requires the
implementation of administrative, technical
and medical procedures. Appropriate advice
to manufacturers and users of vibrating tools
should also be given.
Administrative measures should include
adequate information and training to instruct
the operators of vibrating machinery to adopt
safe and correct work practices. Since
continuous exposure is believed to increase
vibration hazard, work schedules should be
arranged to include rest periods.

42. HEALTH EFFECTS OF
HAZARDS
• Heat : Heat cramps, Heat
exhaustion, Heat stroke, Heat
syncope.
• Cold : Chill blains, Frost bite,
Hypothermia.
• Humidity : Loss of body fluids,
Dehydration.
• Vibrations : Injury and inflammation
of bones, joints and soft tissues.
• Abnormal pressure : Pressure bends,
Caissons disease, Air embolism.

43. Occupational Diseases
• Occupational lung diseases :
Pneumoconiosis : Coal
workers pneumoconiosis
,asbestosis, silicosis.
• Airway diseases : Bysinosis,
Occupational asthma.
• Malignancies : Lung cancer.

44. • Musculoskeletal injuries :
i) Disorders of back, trunk, arm,
leg.
ii) Traumatically induced
Reynaud’s phenomenn.
• Occupational Cancer (other than
lung cancer) : Bladder, Blood, skin,
liver, bones, brain and gonads.
• Severe traumatic injuries :
Amputation, laceration, fractures,
Eye loss, Death.
• Cardiovascular diseases :
Hypertension, Coronary heart
diseases.

45. • Disorders of reproduction :
Infertility, spontaneous
abortions, Birth defects.
• Neurotoxic disorders :
Peripheral neuropathy, C.N.S.
disorders :- encepphalities,
psychosis, personality changes.
• Noise induced hearing loss.
• Dermatologic condition :
Dermatoses, Burns (thermal or
chemical), Contusions,
abrasions.

46. • Psychological disorders :
Alcoholism, substance abuse,
Neuroses, personality disorders.
• Infectious diseases: i) Strange
& exotic :- Brucellosis,
sporotrichosis, anthrax
ii) Lyme disease.
iii) Sexually transmitted
diseases.
iv) HIV infection & AIDS .

47. Exposure Assessment at Work Place.
1. Measurement of the level of hazard in REM
(Relevant Exposure Medium).
4. Measurement of Environmental factors I.e. temperature,
humidity, & Air movement .
3. Measurement of concentration of air borne contaminants
( Dust, Gases, Vapours & Particles .)
4. Collection of Samples from other exposure media.

48. Exposure Assessment of
Individual Worker
1. Measurement of the concentration of harmful agents and their
metabolites in biological samples of exposed worker ( Urine, Blood,
Sputum & exhaled air).
5. Assessment of intensity of biochemical & histological changes due
to exposure.
8. To carry out specialized investigation procedures ( biological Assays
for responses to toxins , cytogenetic assays).

49. Health Hazards of Power plant
workers
• 1) Temperature : Workers are
exposed to high degree of
temperature at boiler rooms,
turbine rooms and other work
stations closer to boilers.
• 2) Health effects : heat
exhaustion due to loss of body
fluids due to excessive
sweating. Signs and
symptoms :- Person feels
weakness , Low body
temperature, rapid pulse ,

50. • 3) Heat cramps : Due to loss of
electrolytes from the body.
• Signs and symptoms :- Painful cramps of
calf muscles and abdominal muscles.
• 4) Heat stroke : Due to exposure to
excessive temperature.
• Signs and symptoms :- high body
temperature i.e. 108 F – 112F, increased
frequency of urination, giddiness and
loss of consciousness.
• 5) Prevention and control : Proper
ventilation and air conditioning of work
place, Use of loose fitting clothes,
provision of effervescent salt drinks to
affected workers, Physical fitness of
workers.

51. • Exposure to Noise : Exposure at boiler
rooms , turbine rooms and other work
stations. Type of noise :- a) steady
wide band noise from continuously
operating motors and machines. b)
Impact noise from steam let outs.
• Effects : social deafness :- person is
habituated for loud talking could not
appreciate whisper, hearing
impairment, Occupational hearing
loss, lack of concentration,
annoyance, mental stress, hyper
tension and peptic ulcer.

52. • Permissible level of noise for
humans : 60 to 85 decibels or 185
Hertz .
• Prevention and control : a) pre-
placement and periodic medical
examination of exposed workers.
Use of protective devices such as
ear muffs and ear plugs. Enclosing
noise producing machines, reduction
of noise by fitting mufflers and
silencers to noisy machines. Sound
proofing of work stations .

53. Coal and other Dusts
• Exposure at coal handling plant,
tippling stations, boiler rooms.
• Respirable dust : dust particles of
0.3 to 5 microns in size.
• Effects of dust inhalation :
respiratory disorders like
pneumoconiosis and progressive
massive fibrosis of lungs.
• Prevention and control : pre-
placement and periodic medical
examination of exposed workers.

54. • Proper ventilation of working place.
• Good house keeping.
• Use of personal protective devices
such as masks and respirators by
exposed workers.
• Dust suppression measures like
wet mopping of the floor, use of
aerosol sprays.

55. Health effects of Radiation
• Exposure at atomic power plants, near
Nuclear Reactor, monitoring panels and
other work stations.
• Permissible level of radiation for humans
: Five rems /year.
• Effects of radiation : high degree of
exposure due to accidental leakage of
Nuclear Reactor causing radiation burns,
acute radiation syndrome, Cancer of the
skin, blood and bones, still births,
intrauterine foetal death, abortions,
shortening of life span.

56. Prevention and Control
• Pre- placement and periodic medical
checkup of workers.
• Shielding the source of radiation :
the source of X-rays, gamma rays
and particulate radiation should be
enclosed in radio protective material
such as lead and concrete of
suitable thickness.
• Distance from the source of
radiation : the controls should be
located as far as possible or
remotely operated.

57. Electromagnetic Field in the
Power Plant
• E.M.F. generates magnetic flux
density at work place and near over
head high tension power transmission
lines, electrical sub stations and
power generation plants.
• Safety limits : maximum field strength
should not exceed 10 Kv /M.
• Recommended continuous exposure
limit : 5 gauss with a maximum of 50
gauss for 2 hours.

58. Effects on Human
Health
• Sleep disturbances.
• Headache.
• Increased susceptibility to
respiratory infections.
• Increased risk of blood and
brain cancer.

59. Prevention and Control
• Insulation and shielding of
machines.
• Barrier operation of machines.
• Continuous monitoring of E.M.F.
level at work place.
• Periodic medical checkup of
exposed workers.

60. Hazards due to social factors
• Workers are affected by industrial
psychoses and neuroses.
• Tensions and worries arising out of
social environments in the industry i.e.
poor intra and inter- personal relations ,
poor housing conditions, separation from
family, job satisfaction and sickness
absenteeism.
• Sickness absenteeism is related to low
productivity and low workers morale .
• Level of absenteeism in the country : to
the tune of 8 – 10 days / head /year.

61. Prevention & Control
2. Periodic Medical Examination of Workers.
4. Provision of good housing facility & Recreational activities.
6. Good intra & inter personal relations in the factory.
8. Health Education & Addiction control programmes in the
Factory.