Safety tips to help agricultural workers beat the heat this summer

Summer temperatures that are cooler than normal have been a welcome change across much of the Midwest this year, but the “dog days of summer” will be back. When temperature and relative humidity levels climb, it is important for workers and employers to prevent heat illness. Heat illness can begin suddenly and includes conditions ranging from heat rash and heat cramps to heat exhaustion and life-threatening heatstroke.
Anyone who engages in strenuous physical activity during summer months when temperature and humidity levels produce high heat indices is at risk for heat illness.  Those who have not acclimated to working in the heat or who have returned to work after being away from it for a week or more are at greater risk of developing heat illness.  Workers in agriculture, construction, trades, utilities, landscaping and building and grounds maintenance are among those at most affected by heat illness.

What circumstances lead to heat illness?
• High temperature and humidity, or “Heat Index.”
The Heat Index, sometimes referred to as the apparent temperature, is a measure of how hot it feels when relative humidity is factored in with the ambient air temperature.  The higher the relative humidity, the less easily the body can cool itself naturally through evaporation of sweat from the skin. Workers should take precautions to prevent heat illness when the Heat Index reaches 91°F and above.
• Dehydration, which limits the body’s ability to regulate temperature through sweating. Drinking alcohol, caffeine, and sugary beverages can contribute to dehydration.
• Wearing clothing that doesn’t allow sweat to evaporate. Too many clothes or clothing that is tight or dark colored can prevent cooling through sweating. Chemical protective clothing that protects the skin from harmful substances can also hold in the heat and prevent evaporative cooling through sweating.
• Low fluid intake that doesn’t make up for liquids lost through sweating.
• Heavy physical labor or exertion.
• No recent exposure to hot workplaces.
• Working in direct sunlight.
Working in enclosed areas with no air movement where the heat index inside can exceed that outdoors (e.g., grain bins, hay mows).

Know the signs and symptoms and how to treat them
Heat exhaustion is a condition that results from exposure to high temperature or high heat index conditions.  Symptoms of heat exhaustion include heavy sweating, headache, nausea, dizziness, weakness, fatigue, weak rapid pulse, muscle cramps (“heat cramps”), dark-colored urine, and cool damp skin with goose bumps.  If left untreated, heat exhaustion can lead to heatstroke.   
If you or a coworker experience symptoms of heat exhaustion, get the person to a shady or air-conditioned area. Have them lie down with their legs elevated and loosen the clothing. Provide cool fluids (not alcohol or caffeine) and moisten their skin with cool wet cloths, water spray, or a cool bath or shower. Seek medical attention if symptoms last longer than one hour or if the person has heart problems or high blood pressure.   
Heatstroke (sometimes called sunstroke) is a life-threatening condition that requires emergency medical treatment to prevent damage to the brain and internal organs. Heatstroke can develop within 10 to 15 minutes when body temperature reaches 104°F or higher. The main indicators of heatstroke are elevated body temperature and changes in mental state, such as confusion, personality changes, or coma. Other symptoms may include rapid pulse, dizziness, fainting, nausea, throbbing headache, irritability, seizures, elevated or low blood pressure, and rapid shallow breathing.  Skin may be hot and dry due to cessation of sweating, or damp, especially after exertion.
Heatstroke can be fatal! If you see someone with signs of heatstroke, call 911 and move them to a shaded or air-conditioned area. Cool the person by soaking their clothing in cool water, applying dampened cloths to the skin, or spraying them with cool water. Provide sips of cool water or sport drinks – but only if they are able to swallow without difficulty - until emergency responders arrive.

Plan ahead to prevent heat illness
Heat illness is preventable by following these steps:
• Check with your doctor to determine if you are taking medications that may make you more susceptible to heat illness.
• Acclimate to hot conditions over several days, gradually increasing the amount of time working in the heat.  Re-acclimation is necessary after being away from working in the heat for several days.
• Wear loose-fitting clothing that is lightweight and light in color. Loose-fitting lightweight clothing helps sweat evaporate to cool the body.  Light-colored clothing does not hold in the heat as much as dark-colored clothing.
• Protect yourself from sunburn. Wear hats with wide brims and use sunscreen on exposed skin.
• Schedule work for early morning or evening hours, when possible.
• Stay hydrated. Start drinking cool fluids before working and continue to drink regularly, up to several times an hour, even before you experience thirst. Drinking about a quart of water or sports drink every hour will help your body sweat and regulate temperature. Avoid alcoholic beverages.  
• Take frequent breaks in the shade or air-conditioned areas. Make a point to drink plenty of fluids during your breaks.
• Work with a partner or buddy and monitor each-others’ condition. Confusion and disorientation are symptom of heat illness that may prevent someone from recognizing they are at risk. Monitor your coworkers and employees for signs of heat illness.  Remind coworkers to drink frequently and take breaks.  Report any symptoms early.
• Use the free Heat Safety Tool App for smartphones to calculate Heat Index risk and determine protective measures to prevent illness.
For more information on preventing heat illness, contact the Great Plains Center for Agricultural Health (GPCAH) at CPH-GreatPlainsCenter@uiowa.edu or 319-335-4405.