Thermo Stress Lawrence S. Wong, CIH University of California Office of the President

Cold Stress

Cold Environment ► Body’s Energy Used to Keep Internal Temperature Warm  Shift Blood Flow From Extremities/Outer Skin to Body Core (Chest & Abdomen)  Results in Rapid Cooling of Extremities and Exposed Skin ► Increases Chance for:  Hypothermia  Frostbite  Trench Foot

Wind Speed ► 16 k/hr (10 mph)  Light Flag Fully Extended ► 24 k/hr (15 mph)  Raises Newspaper Sheet Off the Ground ► 32 k/hr (20 mph)  Wind Capable of Blowing Snow

Hypothermia - Means “Low Heat” ► Body Heat Lost Faster than Replaced  Onset – Body Core Temperature Drops – 95 O F ► Symptoms – Pale & Cold Skin  Shiver, Stomp Feet, Lose Coordination, Slurred Speech, Fumble Items with Hands ► Body Temperature Continues to Fall  Symptoms Worsen, Shivering Stops, Unable to Walk or Stand  Body Temperature of 85 O F - Unconscious  Body Temperature of 78 O F – Death Could Occur

Hypothermia Treatment ► Mild Hypothermia  Move to Warm Area & Stay Active  Remove Wet Clothes & Replace with Dry Clothes or Blanket & Cover the Head  Drink Warm (Not Hot) Sugary Drink  Avoid Drinks with Caffeine ► More Severe Hypothermia – Do All Above and:  Contact EMS  Cover All Extremities Completely & Place Warm Objects on Head, Neck, Chest & Groin  Arms & Legs Are Warmed Last

Severe Hypothermia Treatment ► Treat Victim Very Gently ► Do Not Apply External Heat to Re-Warm ► Hospital Treatment is Required

Frostbite ► Typically Affects Extremities – Feet & Hands ► Skin Freezes and Loses Water ► Usually Occurs at Temperatures < 30 O F ► Affected Body Part – Cold, Tingling, Stringing or Aching, Followed by Numbness ► Skin  Color – Red, Then Purple, Then White  Cold to the Touch  Severe Cases - Blisters

Frostbite Treatment ► Do Not Rub Affected Area to Warm It ► Wrap Area in Soft Cloth ► Move to Warm Area & Contact Medical Personnel ► Do Not Pour Water on Affected Part ► If Affected Part May Get Cold Again Do Not Warm  Warming & Re-Cooling – Cause Severe Tissue Damage

Trench Foot ► Feet Immersed in Cold Water at Temperatures Above Freezing for Long Periods of Time ► Similar to Frostbite, But Not as Severe ► Symptoms – Tingling, Itching, or Burning Sensation. Blisters May Be Present ► Soak Feet in Warm Water & Then Wrap with Dry Cloth Bandages ► Drink Warm Sugary Drinks

Cold Stress Prevention ► Plan for Work in Cold Weather ► Wear Appropriate Clothing – 3 Layers  Outer Layer: Gortex® or Nylon – Break the Wind & Allow Some Ventilation  Middle Layer: Down or Wool – Absorb Sweat & Provide Insulation Even When Wet  Inner Layer: Cotton or Synthetic Weave – To Allow Ventilation ► Layering Creates Air Pockets – Helps Retain Body Heat

Cold Stress Prevention ► Wear Hat – Exposed Head:  Up to 40% Loss of Body Heat ► Insulated Boots or Footwear  Wear One Thick or Two Thin Pairs of Socks  Too Many Socks Tighten Fit & Restrict Blood Flow ► Hands Loose Dexterity < 59 O F ► Change of Dry Clothing–If Clothes Gets Wet ► Do Not Wear Tight Clothing – Loose Air Pocket Insulation

Cold Stress Prevention ► Avoid Alcohol and Caffeine  Increases Heat Loss Through Vasodilation ► Take Breaks Out of the Cold ► Schedule Work During Warmer Parts of Day ► Older Workers or Certain Medical Conditions  May Be More Susceptible ► Radiant Heater ► Shielding Work Areas from Drafts & Wind to Reduce Wind Chill

Cold Stress Training ► Proper Clothing & Equipment ► Safe Work Practices ► Guidelines for Eating & Drinking ► Risk Factors That Increase Health Effects of Cold Exposure ► How to Recognize Signs & Symptoms of Hypothermia, Frostbite, & Trench Foot ► Appropriate First Aid Treatment, Including Warming Procedures

Heat Stress

► Body Produces/Stores More Heat Than You Lose  Metabolism/Exercise  Heat Absorbed ► Radiant Energy (Sun, Fire) ► Conductive (Direct Contact) ► Primary Heat Loss – Evaporation  Sweat/Evaporation  Function of Humidity & Temperature

Heat Illnesses ► Heat Rash  Clogged/Irritated Sweat Glands ► Heat Cramps  Painful Muscle Spasms–Electrolyte Imbalance ► Heat Exhaustion  Heavy Sweating/Pale Clammy Skin  Normal Heart Rate/Body Temperature ► Exert ional Heat Illness  Stuporous Appearance, Nausea, High Temperature, Headache

Heat Illnesses ► Heat Stroke  High Body Temperature  Hot, Red (Gray) Dry Skin, Rapid Pulse  Confusion, Loss of Consciousness  Death is Imminent ► Heat Stroke First Aid  Loosen Tight Clothing  Cool with Wet Cloth  If Conscious, Slowly Give 4 oz of Water Every 15 Minutes  Get Victim to Emergency Room ASAP

Heat Illness Prevention ► Drink Fluids  Water – 4 Cups (1 Quart/Hour)  No Alcohol or Caffeine - Diuretics ► Eat  Replace Electrolytes Lost by Perspiration

Heat Illness Prevention ► Acclimation  Slow Process for Body to Condition Itself to Heat  May Take Up to 10 Days  Quickly Lost in a Matter of Days ► Conditioning/General Health  Stay in Shape, Exercise Regularly  Watch Your Weight

Cal/OSHA Heat Illness Regulation Title 8 Cal. Code Regs., §3395 ► Several Fatalities Due to Heat Stroke in California  Construction  Agriculture ► Became Permanent in April 22, 2006 ► Essentially Identical to Emergency Regulation

Heat Illness Prevention Standard: Application ► All Outdoor Places of Employment ► At Time When Environmental Factors for Heat Illness are Present  Air Temperature  Relative Humidity  Radiant Heat, Conductive Heat  Workload Severity/Duration  Personal Protective Clothing/Equipment

Outdoor Environments ► Agriculture ► Construction ► Equipment and Storage Yard ► Loading Docks ► Tents ► Structures with One or More Open Sides  Lack of Insulation/Heating From Sun  Limited Air Circulation

Potable Drinking Water ► Sufficient Quantity at Beginning of Work Shift  Can Begin Shift with Smaller Quantities if Effective Replenishment Procedures Developed and Implemented ► > 1 Quart/Employee/Hour for Entire Shift  >2 Gallons/Employee/8-Hour Shift ► Encourage Frequent Drinking of Water  Thirst – Unreliable Indicator of Dehydration

Access to Shade ► Available for Employee(s):  Suffering from Heat Illness; or  Believe a Preventive Recovery Period is Needed ► At Least 5 Minutes ► Cool Down (Metabolic Heat/Heart Rate) ► Rehydrate ► Shade is:  Open to Air; or  Provided with Ventilation or Cooling for a Period of No Less Than 5 Minutes ► Access to Shade Permitted at All Times

Heat Illness Prevention Training ► Employee Training ► Supervisor Training ► Training Completed Prior to Assignment in Outdoor Environment with a Potential for Heat Illness

Employee Training ► Risk Factors for Heat Illness  Environmental  Personal ► Employer’s Preventive Procedures ► Importance of Water Consumption ► Importance of Acclimation ► Types/Signs & Symptoms of Heat Illnesses ► Immediate Reporting Signs/Symptoms to Supervisor ► Employer’s Procedures Responding to Signs & Symptoms ► Emergency Medical Procedures

Supervisor Training ► Same Information in Employee Training ► Procedures for Supervisor to Implement Heat Illness Prevention Program to Meeting Cal/OSHA Standard ► Procedures Supervisor to Follow:  When Employee Exhibits Symptoms of Possible Heat Illness; and  For Emergency Response