How to help workers stand the heat

According to the NIOSH publication Working in Hot Environments, the frequency of accidents in hot environments is higher than in more moderate environmental conditions: “Working in a hot environment lowers the mental alertness and physical performance of an individual. Increased body temperature and physical discomfort promote irritability, anger and other emotional states which sometimes cause workers to overlook safety procedures or to divert attention from hazardous tasks.”

If the workers you need to protect can’t get out of the kitchen, what can you do to reduce their risk of heat-related illnesses?

“Well, it’s the same answer we get for everything else—good planning and recognition that you are facing that kind of a hazard,” says Phillip Bishop, professor of kinesiology and director of the Human Performance Laboratory at the University of Alabama.

Kris Bancroft, an OEHS consultant with Tiger Safety Consultants, Dayton, Tenn., agrees, “Preventing the incidence of heat stress requires knowledge, planning, worker acclimatization, training and the use of some engineering and administrative controls. These factors should be considered when designing a heat stress prevention program.”

Know Your Ingredients
A worker can react to heat in a variety of ways, and it is important to recognize all of them. Even conditions that might not be deadly by themselves can cause serious problems. Bancroft shares this story: “In the mid-’90s, a worker employed by a landscaping business was planting bushes at a golf course in south Florida. It was reported that he left his work and walked over to a pond, where he bent over to splash water on his face. He subsequently collapsed and fell into the water. The cause of death was listed as ‘drowning.’”

He continues, “Subsequent to the event, there was no record of the worker’s core body temperature, enzyme levels in the blood or autopsy to determine the presence of aneurysm, yet the statements of the co-workers indicated that the worker was experiencing some degree of difficulty with the heat.”
Preheating

Although IHs and other health and safety professionals are certainly aware of heat-related conditions, it can be helpful to review “Heat Disorders and Health Effects” in the OSHA Technical Manual (see “Hot Web Resources,”). The manual is clear when it describes factors leading to heat-related injuries: Everything from age, weight, degree of physical fitness, degree of acclimatization, metabolism, use of alcohol or drugs, preexisting medical conditions, type of clothing worn and prior heat injury can all affect a worker’s sensitivity to heat. Because of all these factors, it is not easy to predict which workers will be affected —and how they will be affected.

Environmental factors can also come into play. Radiant heat, air movement, conduction and relative humidity are considerations that should be taken into effect. And don’t forget PPE; for instance, a self-contained breathing apparatus can increase the possibility of heat stress due to its weight. Totally encapsulating chemical protection suits can also add to the problem.

“Anything encapsulating—welding gear or other PPE—[makes it] much harder to recognize the symptoms [of heat stress],” says Bishop. “You can’t see your workers very well in this gear.”
He added that it can be difficult to have workers monitor themselves, because often workers aren’t aware of their own body temperature and don’t realize they are having heat-related problems.

Keeping an Eye on the Oven
The ACGIH TLV® for heat stress states, “Excessive heat strain may be marked by … body core temperature greater than 38.5 C (101.3 F) for medically selected and acclimatized personnel; or greater than 38 C (100.4 F) in unselected, unacclimatized workers.” And according to the OSHA Technical Manual, monitoring workers is one of several important steps to reduce heat stress. So how can you tell if a worker is overheated? The answer is awareness.

Daniel Webster, president of Quest Technologies in Oconomowoc, Wis., offers a solution for monitoring heat stress. “With or without protective clothing, the accepted area method for assessment of how much work can be done without danger of heat stress calls for a WBGT (wet bulb globe temperature) monitor.”

Webster points out that there is no perfect solution to the heat stress problem. While they cannot take into consideration several personal factors, WBGT monitors have been successful in the past. “If one needs a good way to assess [personal] factors as well, it would be wise to turn to a personal heat stress monitor,” he says.

But Bishop warns that his lab’s studies show that not all personal monitors are 100 percent effective, and they can lead to a false sense of security. “Our studies are that you get some false negatives,” he says.

HQ Inc. in Palmetto, Fla., manufactures one such personal monitor, the CorTemp system. HQ Product Manager Susan Smith says that their ingestible monitor has “been used for years in research and medicine, but it also has great benefits for industrial [environments]. It is highly convenient, highly accurate and highly safe. It gets to the core of the problem, literally.”

These ingestible monitors are relatively inexpensive, but the cost adds up over time. Also, not all workers want to swallow a radio transmitter. Other personal heat monitors are also available, including ear sensors, heart rate monitors and skin temperature monitors.