Another round of excessive heat is on the way through much of the United States next week, with heat indices predicted to reach 110 degrees Fahrenheit or more in many locations. 

Salah Issa, an expert in farm safety, weighs in with advice for those working outdoors. Issa is an assistant professor in the Department of Agricultural and Biological Engineering, part of the College of Agricultural, Consumer and Environmental Sciences and The Grainger College of Engineering at the University of Illinois Urbana-Champaign. 

What are the risks to outdoor workers in extreme heat?

Salah Issa: Outdoor workers, especially farmworkers, face significant risks due to:

• Prolonged exposure to high temperatures
• Strenuous physical labor
• Limited access to shade, water, and rest
• Piece-rate pay systems for many farmworkers discourage breaks
• Lack of federal OSHA heat standards, though some states have them

Based on research studies, the core body temperature increases nearly 0.5 degrees for every 1% of body mass lost from dehydration during intense physical activity in the heat. As one becomes dehydrated, workers sweat and lose plasma volume and electrolytes. 

These conditions can lead to a spectrum of heat-related illnesses (HRI), including heat rash, heat cramps, heat syncope (fainting), heat exhaustion, and heat stroke, which is life-threatening.

What are the signs to watch for?

Issa: Early signs of heat-related illness include red, itchy bumps in skin folds (heat rash). This is followed by muscle contractions, usually in the legs, that occur after one starts working. These contractions (heat cramps) are forceful and painful. This can be caused by dehydration, loss of sodium and potassium, and fatigue. These cramps are often a warning sign for heat exhaustion. 
Heat exhaustion is the point when one's body cannot maintain its core temperature, and one begins to have a fever along with other symptoms. 

Lastly, we have heat stroke, a multisystem illness where you will see central nervous system (CNS) dysfunction in the form of confusion, loss of consciousness, and seizures because the core body temperature is so high — 104 to 106 degrees — that organs begin to shut down and cannot regulate body temperature.

More information on these conditions can be found on farmdoc’s YouTube channel.

What can outdoor workers and employers do to decrease the risk?
Issa: Prevention principles include:

• Written and verbal safety instructions
• Encouraging hydration (8 ounces (250 milliliters) every 15 minutes)
• Providing shade and rest breaks
• Acclimatization (gradual exposure for new/returning workers)
• Monitoring high-risk individuals

Additional strategies:

• Adjust work hours to avoid peak heat
• Use buddy systems to monitor symptoms
• Provide medical screening and training
• Ensure water and bathrooms are readily accessible

What policies could improve health and safety for outdoor workers?

Issa: Currently, there is no federal OSHA heat standard, and field sanitation rules don’t specify proximity of water/bathrooms. Small farms (≤10 workers) are exempt from many regulations, and immigration status is often used to suppress complaints. In addition, piece-rate pay discourages breaks and hydration.

Policy improvements could include:

• A national heat standard
• Mandatory acclimatization protocols
• Stronger enforcement of existing sanitation and safety rules
• Worker protections regardless of immigration status

Contact news@aces.illinois.edu to arrange interviews with Issa.