In the oppressive heat and humidity of summer, heat illness can strike suddenly and with a vengeance. Immediate action is required. Every year, more than 30 workers develop heat stroke and die.

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LIUNA General President Terry O’Sullivan

“Heat-related illness is a major concern for Laborers and LIUNA signatory contractors,” says LIUNA General President Terry O’Sullivan. “Laborers and onsite supervisors must be alert and well-prepared. All outdoor construction presents heat-related risks, but highway construction, especially in the south and southwest and in more remote areas, poses significant danger.”

At the same time, with proper precautions, the danger of heat illness is readily avoided. To reduce risk:

  • Drink water often
  • Rest in the shade
  • Report heat symptoms early
  • Know what to do in an emergency

“Heat illness is common,” says O’Sullivan, “but if you stay hydrated and take your breaks in the shade, your risk is minimized. The most serious consequences can be avoided with quick action when the signs of heat stress appear.”


High heat raises the body’s temperature and causes sweating. Sweating cools by evaporation, which is easiest when the surrounding air is dry, breezy and able to absorb moisture. High humidity makes sweating less efficient. The LHSFNA’s chart, Heat Equation, shows the relationships between heat and humidity and marks the danger zone as days when the temperature hits 95°F with humidity over 60 percent.

Generally, heat illness develops in two stages. First, an individual experiences heat exhaustion. Common signs include:

  • Headaches, dizziness, lightheadedness, fainting
  • Moist skin
  • Irritability or confusion
  • Upset stomach, vomiting

At the first signs of heat exhaustion, the victim should be moved to shade and encouraged to sip cool water. If the victim’s temperature is high (102 degrees or more) or if other symptoms do not abate within an hour, medical assistance is required.

Heat exhaustion can develop into heat stroke, indicated by:

  • Dry, hot skin with no sweating
  • Confusion, loss of consciousness
  • Seizures or convulsions

If heat stroke develops, immediate action is required.Call 911 and place the victim in a shaded area. Wipe the skin with cool water, loosen clothing and fan with cardboard or other material until medical assistance arrives.


This summer, OSHA is making heat illness the focus of a national outreach initiative. The agency created a new heat illness website and is stepping up enforcement efforts. In contrast to California and Washington, which have specific heat stress standards, OSHA must rely on the General Duty Clause to protect outdoor workers. The clause states, “Each employer shall furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees.”

Heat Stress Materials

LIUNA signatory employers, local unions and training centers can tap a number of LHSFNA heat-related publications to assist their efforts. In addition to Heat Equation, the Fund publishes a training manual, Heat Stress Education for Laborers, and a health alert, Heat Stress in Construction. All are available through the online publications catalogue.

The OSHA site provides links to posters and other resources (in Spanish and English), including brief heat stress messages from Secretary of Labor Hilda Solis and OSHA Director David Michaels.  As part of its initiative, OSHA is partnering with the National Oceanic and Atmospheric Administration (NOAA) to ensure that NOAA’s weather service alerts incorporate worker safety precautions. The safety information will be published on NOAA’s Heat Watch webpage.

[Steve Clark]