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 • Indoor • Foundry workers • Steel workers • Oven/Furnace workers • Glassblowers • Outdoor • Farmers • Postage workers • Ranchers • Military personnel • Fishers • Construction workers

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

12. Heat stroke • Signs and symptoms: • 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: • 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 • 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 40-42 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 • 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 units 8 6 4 2 -2 -4 -6 10 10 10 10 1 10 10 10 Radio Infrared V Ultra-Violet X-Rays Cosmic Rays i Light s i b l e Gamma Rays 4 - 10 -8 -6 -4 -2 2 2 2 10 10 10 10 10 1 10 10 Photon energy in million electron volts (MeV)