Beating the Heat

May 1, 2000
Learn how you can help your employees stay cooler -- and healthier.

Jose Taragano says heat stress management is a key occupational health initiative for his company. Taragano is the corporate director of environment, health and safety for Alcoa Inc., the world's leading producer of aluminum. "When you have molten aluminum metal in smelting pots and employees sometimes have to get in very close proximity to that molten metal, it becomes an extremely hot work environment."

Of course, foundry workers are not the only employees susceptible to heat stress. Just ask Ralph Bollinger, senior associate for safety and OSHA at Houston-based ExxonMobil Chemical Co. "During the summer -- and summer here lasts four to five months -- it's not unusual for highs to be over 95 degrees with more than 90 percent humidity," Bollinger reported.

Taragano and Bollinger know that heat-related health problems afflict workers who are not acclimated to a hot environment as well as workers who seem otherwise protected. That is why heat stress management is a top priority of their EHS departments.

Heat-Related Illnesses

Heat stress is the combination of factors that include air temperature, air movement, humidity and physical work that determines the total heat load on the body. Several medical conditions can result, varying in severity:

Heat rash occurs in hot and humid environments where sweat is not easily removed from the surface of the skin by evaporation. The result is a red, bumpy rash that often itches. Heat rash can be treated and prevented by keeping the skin dry and clean.

Heat syncope, or fainting, may be a problem for the worker unacclimated to a hot environment who simply stands still in the heat. The fainting results from blood pooling in the legs, causing less blood to be delivered to the brain. Victims usually recover quickly after a brief period of lying down. Moving around, rather than standing still, will usually reduce the possibility of fainting.

Heat cramps are painful muscle spasms that usually follow strenuous work. The primary cause is loss of body salt in sweat. Victims should drink electrolyte drinks to relieve the symptoms.

Heat exhaustion results from loss of fluid through sweating when a worker has failed to drink enough fluids, take in enough salt or both. The worker with heat exhaustion still sweats but feels weak, giddy or nauseated. The skin may be clammy and moist, the complexion pale or flushed, and the body temperature normal or slightly higher. Treatment is usually simple: The victim should rest in a cool place and drink an electrolyte solution. Severe cases involving victims who vomit or lose consciousness may require longer treatment under medical supervision.

Heat stroke is the most serious health problem for workers in hot environments. Because the body of a person suffering from heat stroke does not sweat, excess heat is not released, causing the body temperature to rise to dangerous levels. A victim's skin is warm and dry, and he may be confused, delirious and experience convulsions or loss of consciousness. Victims of heat stroke will die unless treated promptly. While awaiting medical help, the victim must be moved to a cool area, given plenty of fluids and cooled as adequately as possible.


The good news about heat-related health problems is that they can be prevented or the risk of developing them can be reduced. Safety personnel at ExxonMobil Chemical and Alcoa offer several proven heat-reduction methods.

Engineering controls. Controls can include general ventilation or spot cooling by local exhaust ventilation at points of high heat production. "In some cases, we've brought in air-conditioned air, and we've stationed vents directly over the main work platform where the employee would be working," ExxonMobil's Bollinger explained. "When employees are doing most of their tasks, they are actually standing under a stream of cool air."

Alcoa also relies upon engineering controls, according to Bob James, corporate industrial hygiene technical manager. He suggested substituting machinery for manual labor in certain heat-intensive environments. "Instead of having workers manually get on top of a [smelting] pot, we now use overhead cranes to perform that function, separating workers from the heat," James said.

Work scheduling. If possible, heavy work should be scheduled to reduce heat exposure. "If we can plan the work at a cooler time of year, we do that," Bollinger said. Often times, however, seasonal planning is not an option. "In those instances, because most of our facilities are 24-hour-a-day operations, we can change when the work is done." ExxonMobil often will have certain jobs done by an evening or early-morning crew rather than an afternoon crew.

Alternate work and rest periods. Enforced breaks with longer rest periods in a cool area can help workers avoid heat stress. ExxonMobil has developed guidelines and tables that consider temperature and humidity alongside the level of work involved (light, moderate or heavy), and whether workers must wear protective -- and often impermeable -- clothing, to develop a system of enforced breaks. "Depending on these factors, an employee may work 45 minutes with the following 15 minutes spent in an enforced rest. Usually, we try to get them into a shaded area or where there are fans or other cooling devices, but we make sure that their body has a chance to expel the heat and recover."

Provide fluids. Work practices such as providing plenty of drinking water or electrolyte-balanced fluids can help reduce the risk of heat disorders. "We supply water and, in some cases, electrolyte drinks, and we require workers to drink at least a cup every 20 to 30 minutes," Bollinger said.

Acclimatization. "People who go on a week's vacation can mistakenly think that they can withstand the same amount of heat that they did just the week before," James said. "You can't just go into a hot job and work full throttle off the bat." Instead, returning employees, as well as new employees, require acclimatization to the heat through short and gradually longer periods of work in the hot environment to reduce the risk of heat stress.

Heat index alarms. Alcoa has established heat index alarm systems at each of its locations that are triggered by high heat levels. "If you're in, for example, Texas and the temperature and humidity reach a certain level, these conditions would trigger a heat index alarm," James explained. When certain trigger levels are reached, additional controls (e.g., engineering controls, acclimatization schedules, restrictions on overtime) take effect.

Medical surveillance. An integral part of Alcoa's program is medical surveillance. "We prescreen employees who are at a potentially increased risk of heat-related illness," James said. "Personal conditions -- if a worker has an underlying medical condition or is taking certain types of drugs or medications -- could place a worker at higher risk of developing a heat-related illness." Alcoa has instituted an annual screening process to evaluate employees' risk levels.

Employee education and participation. Employees should be trained to detect heat stress in themselves and in their fellow workers, according to Bollinger. "Whether it's through regularly scheduled meetings or simply posting signs where employees can see them, employees need to be aware of the warning signs of heat-related illnesses."

Because of their prevention efforts, Taragano and Bollinger said that only a handful of their companies' workers are treated for heat stress, despite the heat-intensive conditions inherent to their industries. They credit their success to their companies' efforts to educate and protect employees with effective heat stress prevention programs.

No heat stress program would be complete, however, without employee input, according to Taragano. A key to Alcoa's heat prevention program is management's willingness to take into consideration employee suggestions. "For example, if you are evaluating new personal protective equipment, employee participation is very important," he said, because, ultimately, it is employees who have first-hand knowledge of what works and what can be improved.

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