Urgent Reminders

Heat stress is preventable but can quickly spiral into a deadly hazard. As the climate in some parts of the country becomes hotter and drier, this threat is rising.

“Schwarzenegger Acts on Heat Death Toll” —Associated Press, July 13, 2007

Don’t be surprised if you read more headlines like this one in the summer ahead. Our summer months are getting hotter, and the threat to outdoor workers is rising with them.

California Gov. Arnold Schwarzenegger visited the state’s central valley growing area on July 27, 2007, to mark the day that California’s first-in-the-nation heat illness prevention regulation became permanent. He made the trip during a record-breaking heat wave and explained why the regulation was needed.

“As the record heat wave continues, we must protect our outdoor workers in the sweltering summer heat,” the governor said. “It is critical that employees working outdoors, like farmworkers, highway workers, landscapers, and construction workers, drink plenty of water and take rest breaks in the shade. Our heat illness regulations have made California a national leader for workplace standards for heat illness prevention and treatment.”

Schwarzenegger introduced the rule after nine heat deaths were recorded among workers in California in July 2005. The regulation requires employers and workers to know how to spot, prevent, and treat heat stress. Access to a shaded area must be available to any outdoor worker who feels the need to cool off and get out of the sun, and water must be made available to outdoor workers at all times.

At www.dir.ca.gov/DOSH/HeatIllnessInfo.html, Cal/ OSHA offers online heat illness prevention guides in English and Spanish that are specifically for agricultural workers and hot indoor environments. Another document there is a sample procedure for employers to use to prevent heat stress illnesses.

Heat stress occurs when the body cannot release heat and cool itself. Working hard in high heat lessens the body’s ability to cool itself, and as a result, the body’s core temperature and heart rate rise.

A program to prevent heat illness will protect workers’ health and also improve the safety of your operation, because even mild heat illness can impair an employee’s judgment and performance. Workers are also more productive when they are protected from heat illnesses.

A worker can become able to tolerate heat through the process called acclimatization. But progressively more serious heat illnesses can affect any worker:

Heat rash, known as prickly heat, can occur in hot, humid environments where sweat is not easily removed from the surface of the skin by evaporation. This is prevented by having the worker rest in a cool place. Heat syncope (fainting) affects workers who haven’t become acclimatized. Victims usually recover quickly after lying down for a short time.

Heat cramps are muscle spasms by drinking lots of water but not replacing the body’s salt loss. Tired muscles are most likely to cramp.

Heat exhaustion results from loss of fluid through sweating when the worker has not drunk enough fluids, taken in enough salt, or both. He still sweats but experiences extreme weakness, giddiness, nausea, or headache. The skin is clammy and moist, and body temperature is normal or slightly higher. He should rest in a cool place and drink an electrolyte solution to restore potassium, calcium, and magnesium salts quickly.

Heat stroke, the most serious health problem facing workers, causes confusion, delirium, and loss of consciousness. Individuals suffering this malady will have a body temperature of 106 degrees F or higher and hot, dry skin that may be red, mottled, or bluish. Victims will die without prompt treatment. Move them to a cool area and soak their clothes with cool water, fanning vigorously to increase cooling.

OSHA’s heat stress topics page remains an excellent resource for guidance and materials about this topic. You can find a fact sheet, guides, QuickCards, a list of relevant standards, and training programs.

At a related page, you’ll find a discussion of appropriate PPE and numerous online resources for construction safety.

Good Practices to Avoid Illness
Following these steps will help your workers avoid heat illnesses:

Have them drink plenty of fluids when working in hot environments, even if they aren’t thirsty.

They should remain physically fit to increase their tolerance for heat.

Schedule frequent breaks in shaded rest areas and ensure the most strenuous labor is performed at cooler times of the day.

Acclimatize them to the heat, a process than can take up to three weeks.

Learn about the medications and medical conditions that can worsen the effects of heat stress, and train employees about them.

Have them wear sun-protective clothing.

Train them, as California requires, to recognize signs and symptoms of heat stress.

Update your emergency action plan with procedures for addressing heat illnesses. Make copies available wherever employees are working in hot areas, inside or outside.

Considering using cooling devices, such as cooling vests and large fans.


This article originally appeared in the March 2009 issue of Occupational Health & Safety.

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