1. PHYSICAL HAZARDS
H.R.Sarreshtahdar, MD

2. Physical hazards Heat Cold Vibration Radiation
Atmospheric pressure changes

3. HEAT

4. How does body get rid of heat?
Conduction
Convection
Radiation
Evaporation

6. Factors affect body temperature
Air temperature
Radiation
Air motion
Humidity
Type of clothing
Time exposed
Workload
Age/sex/race
Mass/weight
Health status
Diseases
Drugs
Acclimatization status

7. WBGT index The most important index of workplace heat exposure
Calculation:
Air temp.
Air motion
Radiant heat
humidity

8. Heat Balance

9. Body response to heat Peripheral vasodilatation Sweating
Change in metabolic rate
Increased plasma & fluid volume

10. Occupational exposure to heat
Outdoor
Farmers
Postage workers
Ranchers
Military personnel
Fishers
Construction workers
Indoor
Foundry workers
Steel workers
Oven/Furnace workers
Glassblowers

11. Heat-related syndrome
Heat stroke
Heat exhaustion
Heat cramps
Heat syncope

12. Heat stroke Signs and symptoms: Laboratory:
Cerebral dysfunction and altered mental status
Hyperpyrexia (core temperature → 41.1°C)
hot, dry skin (classic), or moist skin (exertional)
Seizure, coma, tachycardia, hypotension
Laboratory:
↑leukocytes, ↓ serum K, Ca, P, ↑ BUN, CPK, ALT, AST
Concentrated urine with myoglobinuria, pr.uria, tubular casts
Hyperuricemia, DIC, thrombocytopenia

13. Heat stroke Treatment: Rapid reduction of body temperature:
In the workplace:
Shady cool place
removing clothes
use evaporative cooling (The best method):
spraying entire body with cool water, blowing cool air to the body Or Use ice packs, or water immersion

14. Prevention Avoid reexposure to heat at least for 4 weeks
Work-rest regimens according to heat TLV
acclimatization
Engineering controls
Special suits
Shaded rest areas
Cool drinking water or electrolyte/carbohydrate solutions

15. Heat exhaustion Strenuous work in hot climates
Volume/electrolyte depletion
Core temperature > 38°C
Symptoms and signs:
Intense thirst, weakness, nausea, headache, confusion, tachycardia, profuse sweating, moist skin
Important: may progress to heat stroke
Treatment: placing the patient in a cool and shaded area, provide hydration and salt (oral or IV)

16. Heat cramp Salt deficiency (replacement of sweat loss with water)
Symptoms and signs:
Painful muscle contractions, weakness, nausea, vomiting
Moist and cool skin
Euthermia
Elevated CPK
Move the patient to a cool environment + balanced salt solutions (4tsp salt per gallon of water)
1-3 days rest + salt supplementation

17. Heat syncope Sudden unconsciousness after strenuous work
Cutaneous vasodilation
Cool, moist skin
Hypotension
Treatment:
cooling and liquids

18. Prevention Worker selection Acclimatization Work-rest cycles
Availability of cool places
Availability of cool drinks

19. COLD STRESS
IN THE WORKPLACE

20. Body reaction to cold environment
Increase heat generation
Shivering
Decrease heat loss
Vasoconstriction

21. Risk factors Alcohol Opium CNS depresants Alpha agonists & antagonists
Direct vasodilatator
Beta antagonists

22. Cold-induced diseases
Systemic
Local
Freezing
Frost bite
Non-freezing
Immersion foot

23. Systemic hypothermia
Body core T <35°C
Mild
Moderate
Severe

24. Treatment Remove wet garments Protect against heat loss
Maintain horizontal position
Avoid excess movements
Monitor core temperature
Monitor cardiac rhythm

25. Treatment Pulse present: Pulse absent:
Adequate ventilation and O2 administration
Electrolyte and acid-base correction
Blood pressure correction
Rewarming:
Passive rewarming
Active external rewarming (warm blankets, warm baths)
Active internal rewarming (blood, peritoneal dialysis, heated air)
Pulse absent:
CPR until core T> 35
rewarming

26. Prevention Wind chill index Prevent core T from falling below 36°C
Temperature
Wind velocity
Prevent core T from falling below 36°C
Work-rest cycles according to WC index and work intensity
Suitable clothes
Wind-protected, warm shelters
Available hot food and drinks

27. Frostnip Frostnip is the freezing of upper layers of the skin.
Characterized by:
- white, waxy skin.
- general numbness
Frostnip is generally reversible and does no major tissue damage.

28. Frostnip - treatment
Gently warm area by blowing warm air on it or by placing it near a warm body part.
DO NOT rub the area! Rubbing can rupture frozen cells, causing extensive damage.
Frostnip is a warning sign of possible frostbite

29. Frostbite
Frostbite is a freezing of the surface and deep layers of tissue.
Characterized by:
- white, and feels “woody”
- numbness, possible anesthesia
- deep frostbite can affect bone and muscle
- purple/black color is from ruptured blood vessels

31. Frostbite - treatment
Immerse affected area in degrees C water until thawing is complete.
- part will be extremely painful
Wrap affected part in sterile gauze
Affected part should not be used for anything
- keep part from refreezing

32. Immersion Foot – trench foot
Immersion foot is caused by prolonged exposure of the feet to wet, cool conditions.
Characterized by:
- yellowish, smelly feet
- possibly numb
- sloughing of skin tissue/itching
*Immersion foot may cause permanent damage to foot tissues, leaving person susceptible to cold injuries in future.

33. Immersion Foot - treatment
Careful washing and drying of feet.
Keep feet dry as much as possible.
Keep off feet as much as possible until healed.

34. VIBRATION

35. Types
Whole- body vibration
Segmental vibration

36. WBV A kind of cummulative trauma
Jobs: drivers, miners, heavy equipment operators
Frequency: 1 – 80 Hz (esp. below 20 Hz)
Two types: vertical (4-8Hz)
horizontal (1-2Hz)

37. Disorders
Musculoskeletal (LBP, Disk degeneration, disk calcification, …)
Neurological (decreased visual acuity, Labyrinth disorders, insomnia,…)
Circulatory
Digestive
Reproductive (abortion, congenital malformation, …)

38. Prevention ↓ exposure duration ↓ unnecessary exposures Isolation
Careful maintenance of machines
Resting after exposure

39. Segmental Vibration Frequency: 5-5000 Hz (esp. 125-300 Hz)
Jobs: work with chain saw, grinder, sander, pneumatic drill, jackhammer
Disorders: HAVS (Vibration-induced white finger)

40. HAVS A kind of secondary Raynaulds phenomenon Signs and symptoms:
numbness and tingling → blanching →
cyanosis → atrophy → ulceration → gangrene
Advanced disease: bone and cartilage degeneration, joint stiffness, clumsiness

42. Treatment Removing from more exposure Massage, Shaking, Warm water
Nifedipine
PGE

43. Prevention Better tool design Anti-vibration gloves HAV standards
Work practices
Medical surveillance
Work/rest cycles

44. Work practices A/V gloves Adequate clothing Keep the hands warm
Avoidance from wetting the hands
Avoidance from smoking
Let the tool do the work
Maintain tools carefully

45. Types of radiation Ionizing Non-ionizing Electromagnetic energy
X-ray
Gamma ray
Subatomic particles
Electron
Proton
Α particle
Non-ionizing

46. Definition: energy in the form of particles or waves
Types of radiation
Ionizing: removes electrons from atoms
Particulate (alphas and betas)
Waves (gamma and X-rays)
Non-ionizing (electromagnetic): can't remove electrons from atoms
infrared, visible, microwaves, radar, radio waves, lasers

47. Radiation wavelength in angstrom units10 8 6 4 2 -2 -4 -6
X-Rays
Radio
Infrared V i s b l e
Ultra-Violet
Light
Gamma Rays
Cosmic Rays - -8
Photon energy in million electron volts (MeV)