Outdoor Worker Safety

Heat Cramps
Prolonged exercise in hot environments may lead to involuntary spasms or cramping in muscles. These are usually more intense and prolonged than a typical leg cramp. It is most common for muscles in your calves, arms, abdomen, or back to be affected but heat cramps may occur in any muscle group that is being utilized during your activity.

How to Respond:

• Rest and allow your body to cool down
• Hydrate and consider having some juice or a sports drink
• Gently massage and stretch the cramping muscles
• Avoid strenuous activity for several hours
• Contact your doctor if the cramps do not go away after an hour

Read more: https://www.mayoclinic.org/first-aid/first-aid-heat-cramps/basics/art-20056669

Heat Exhaustion
Heat exhaustion is a result of your body becoming overheated due to prolonged exposure to high temperatures. This may be compounded by strenuous physical activity (such as fieldwork) and high air humidity.

Symptoms Include:

• Heavy sweating
• Rapid but weak pulse
• Skin that feels cold, pale, and clammy to the touch
• Muscle cramps
• Weakness or fatigue
• Headache and/or dizziness

How to Respond: 
Move the person to a cool place (shade, air conditioned vehicle, nearby building, etc.) and take steps to cool them with wet clothes. Apply wet clothes or ice packs to areas of the body with major arteries such as the neck and armpits. This will speed the cooling of the core body temperature.

It is possible that the victim may lose consciousness. If they do, continue to monitor their breathing and heart rate closely and continue efforts to cool them. If symptoms persist for longer than 1 hour, conditions worsen, or the victim is throwing up, contact emergency medical services. Untreated, heat exhaustion may lead to heat stroke which is an immediate medical emergency.

Read more: https://www.mayoclinic.org/diseases-conditions/heat-exhaustion/symptoms-causes/syc-20373250

Heat Stroke
Heat stroke is the most severe heat illness and is specifically characterized by a body temperature that exceeds 104°F/40°C. If left untreated, heat stroke can damage critical organs such as the brain, heart, and kidneys, and in extreme cases may lead to death. Sudden exposure to hot weather, such as traveling to a hotter climate to conduct fieldwork, can increase the risk of heat stroke. Certain health conditions and medications may also increase your risk so always start slow and evaluate how you (and your team) are responding to the environment.

Symptoms Include:

• Hot, red skin. May be damp or dry to the touch
• Fast, strong pulse
• Confusion and/or slurred speech
• Headache and/or dizziness
• Nausea

How to Respond: 
Call 9-1-1 immediately. Heat stroke is a medical emergency. After contacting emergency services, move the person to a cooler place (shade, air conditioned vehicle, nearby building, etc.) and take steps to cool them by applying damp clothes. If possible, place them in an ice-bath but be sure to monitor their condition closely and be prepared to support their body.

It is possible that the victim may lose consciousness. If they do, continue to monitor their breathing and heart rate closely and continue efforts to cool them.

If the person starts to vomit, place them in the recovery position to avoid a choking hazard. In the case of heat stroke, you do NOT want to give the person anything to drink because it may induce vomiting or the person may not be able to swallow properly.

Read more: https://www.mayoclinic.org/diseases-conditions/heat-stroke/symptoms-causes/syc-20353581

• The Heat Index gives only a quick “feel” of the outside environment.
  • It based on only two factors: the air temperature and the relative humidity.
  • It is measured in the shade, and combines air temperature and relative humidity to represent how hot the conditions feel at rest.  The heat index does not account for the effects of wind, sunlight, radiant heat sources, or workload.
• The Wet Bulb Globe Temperature (WBGT)  is the core tool used by occupational health professionals because it measures all four factors that contribute to heat stress in workers:
  • Ambient air temperature.
  • Humidity (high relative humidity makes it difficult for the body to cool itself through sweating).
  • Radiant heat from sunlight or artificial heat sources such as furnaces.
  • Air movement (in most situations, wind helps workers cool off).

While local weather reports (= heat index) can be useful, the readings from these stations may not reflect the conditions at the specific worksite (or playing field, etc.).  Weather reports can be inaccurate if the specific work/field site has features that affect heat conditions. These features include:

• Indoor work — a weather report cannot gauge conditions inside a building.
• Direct sunlight — weather services measure temperature and Heat Index in the shade.  Work in the sun may be considerably hotter.  Direct sunlight can increase Heat Index by up to 13.5°F (7.5°C).
• Heat sources — weather reports cannot account for the heat generated by fires, hot tar or other materials, ovens, or other hot equipment, or heat-absorbing surfaces such as roads and roof surfaces.
• Wind blockage — some worksites may be hotter than surrounding areas because of structures that block air movement.  Examples include trenches, and bowl-shaped athletic stadiums, and the leeward side of buildings (especially if in direct sunlight).
• Reflective material — water, metal, or other materials can reflect sunlight onto workers.

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Below are two options to determine how long a person can work in a hot environment, and how long the rest break should be.

Option 1: Use the NIOSH Heat Stress Work/Rest Schedule.

• It is based on local air temperature, with adjustments for direct sunlight and humidity.
• The NIOSH Schedule:
  • It is not as accurate as using the WBGT (which takes measurements in the exact work/field site).
  • You must incorporate the temperature adjustments on page 2 to account for sunshine and humidity levels.

Option 2:  Use the WBGT Work/Rest Schedule and follow the guidelines in this table.  The table is based on the following considerations:

• The Wet Bulb Globe Temperature.
• The type of work (light, moderate, heavy).
• If the person is acclimatized or not to the conditions.
• Water consumption per hour.
• The work/rest cycle per hour.

NIOSH Cold Stress Homepage:  Information for workers who are exposed to extreme cold or work in cold environments.

• National Weather Service current hazardous weather conditions & forecasts for the St. Olaf  campus lands
• Rice County SKYWARN: Facebook
• A real-time weather radar app (like WeatherBug)

• NOAA Severe Weather Safety Tips – To Save Your Life!

• If thunder roars, go indoors! 
• If you can hear thunder, you are close enough to be in danger from lightning.  The National Weather Service recommends staying inside for at least 30 minutes after the last thunder clap.
• If caught outside:
  • Crouch close to the ground.  If you are caught in an open area, crouch down in a ball-like position (feet and knees together) with your head tucked and hands over your ears so that you are down low with minimal contact with the ground.
  • Do NOT lie down.  Lightning causes electric currents along the top of the ground that can be deadly over 100 feet away.  Crouching down is the best combination of being low and touching the ground as little as possible.
  • Separate from each other.
    If you are in a group during a thunderstorm, separate from each other.  This will reduce the number of injuries if lightning strikes the ground.