PHYSICAL PHYSICAL HAZARDSHAZARDS

H.R.Sarreshtahdar, MDH.R.Sarreshtahdar, MD

Physical hazards

Heat

Cold

Vibration

Radiation

Atmospheric pressure changes

HEAT

How does body get rid of heat?

Conduction

Convection

Radiation

Evaporation

Factors affect body temperatureo Air temperature

o Radiation

o Air motion

o Humidity

o Type of clothing

o Time exposed

o Workload

o Age/sex/raceo Mass/weighto Health status

DiseasesDrugs

o Acclimatization status

WBGT index The most important index of workplace

heat exposure

Calculation:

• Air temp.

• Air motion

• Radiant heat

• humidity

Heat Balance

Body response to heat

Peripheral vasodilatation

Sweating

Change in metabolic rate

Increased plasma & fluid volume

Occupational exposure to heat

Outdoor

o Farmers

o Postage workers

o Ranchers

o Military personnel

o Fishers

o Construction workers

Indoor

o Foundry

workers

o Steel workers

o Oven/Furnace

workers

o Glassblowers

Heat-related syndrome

Heat stroke

Heat exhaustion

Heat cramps

Heat syncope

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

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

PreventionPrevention 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

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)

Heat cramp Salt deficiency (replacement of sweat loss with

water) Symptoms and signs:Painful muscle contractions, weakness, nausea,

vomitingMoist and cool skinEuthermiaElevated CPKMove the patient to a cool environment + balanced

salt solutions (4tsp salt per gallon of water)1-3 days rest + salt supplementation

Heat syncope

Sudden unconsciousness after strenuous

work

Cutaneous vasodilation

Cool, moist skin

Hypotension

Treatment:

cooling and liquids

Prevention

Worker selection

Acclimatization

Work-rest cycles

Availability of cool places

Availability of cool drinks

COLD STRESS IN THE WORKPLACE

Body reaction to cold environment

Increase heat generation

Shivering

Decrease heat loss

Vasoconstriction

Risk factors

Alcohol

Opium

CNS depresants

Alpha agonists & antagonists

Direct vasodilatator

Beta antagonists

Cold-induced diseases

Systemic

Local

Freezing

Frost bite

Non-freezing

Immersion foot

Systemic hypothermiaBody core T <35°C

Mild

Moderate

Severe

Treatment

Remove wet garments

Protect against heat loss

Maintain horizontal position

Avoid excess movements

Monitor core temperature

Monitor cardiac rhythm

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

PreventionPrevention 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

FrostnipFrostnipFrostnip 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.

Frostnip - treatmentFrostnip - treatmentGently 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

FrostbiteFrostbiteFrostbite 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

Frostbite - treatmentImmerse affected area in 40-42 degrees C

water until thawing is complete.- part will be extremely painful

Wrap affected part in sterile gauzeAffected part should not be used for

anything- keep part from refreezing

Immersion Foot – trench footImmersion 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.

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.

VIBRATION

Types

Whole- body vibration

Segmental vibration

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)

Disorders Musculoskeletal (LBP, Disk degeneration,

disk calcification, …) Neurological (decreased visual acuity,

Labyrinth disorders, insomnia,…) Circulatory Digestive Reproductive (abortion, congenital

malformation, …)

Prevention

↓ exposure duration

↓ unnecessary exposures

Isolation

Careful maintenance of machines

Resting after exposure

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)

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

Treatment

Removing from more exposure

Massage, Shaking, Warm water

Nifedipine

PGE

Prevention Better tool design

Anti-vibration gloves

HAV standards

Work practices

Medical surveillance

Work/rest cycles

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

Types of radiationTypes of radiation Ionizing

Electromagnetic energy X-ray Gamma ray

Subatomic particles Electron Proton Α particle

Non-ionizing

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

Radiation wavelength in angstrom units

108 106 104 102 1 10-2 10-4 10-6

X-RaysRadio Infrared Visible

Ultra-VioletLight

Gamma Rays

Cosmic Rays

10-10 10-8 10-6 10-4 10-2 1 102

Photon energy in million electron volts (MeV)

22 4 10