Be mindful of heat stress dangers on the farm

A sudden rise in temperature forecast for much of California in the coming week could put outdoor workers at greater risk for heat related illnesses, according to Howard Rosenberg, University of California Berkeley Cooperative Extension agricultural personnel management specialist.

“When a body is working hard in any weather, it generates and needs to dissipate a lot of internal heat,” Rosenberg said.

In addition, workers may not yet be “acclimatized” to hot weather, which takes a week or two.

“The sudden change in weather this early in the year may catch many workers before they are ready to cope with the same level of heat that they would be able to later in the season,” Rosenberg said.

Key to controlling heat stress at any stage of acclimatization is drinking enough water to replenish fluid the body loses as sweat in cooling itself. A state regulation adopted two years ago requires all employers to protect their outdoor workers from heat stress by providing a quart of water per hour, a shaded area and time to rest there when necessary, and training in heat illness prevention.

Rosenberg has worked extensively with growers to prevent heat-related discomfort, impaired performance, accidents, and heat illnesses that threaten workers’ safety and even lives.

In partnership with the California Farm Bureau Federation and with support from the USDA Western Center for Risk Management Education, he compiled key points on heat stress prevention concisely in Spanish and English on pocket-sized fold-out cards. They may be downloaded for free from the UC ANR Web site at

The Web site also has links to UC articles titled “Ten key points about heat stress,” “UC gives tips for coping with heat stress,” “Heat illness symptoms and first aid,” and “How heat affects the body.”

In addition, the Web site has information about audio recordings on heat stress in Spanish and English, which are available by calling (800) 514-4494.

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