For people who work outside or in hot conditions, it can be perilous when temperatures rise during the summer months.

The U.S. Department of Labor’s Occupational Safety and Healthy Administration warns that thousands of people become ill from occupational heat exposure every year — and some people die from heat exposure at work.

The start of the summer season when the mercury rises can be a dangerous period.

That’s because most outdoor deaths due to heat exposure occur in the first few days of working in a hot environment “because the body needs to build a tolerance to the heat gradually over time,” according to OSHA’s website on heat exposure.

The agency says employers have a duty to protect workers against heat, and should provide adequate cool water, rest breaks, and shade or a cool rest area for employees.

Specifically, OSHA says employers should encourage workers to drink water every 15 minutes and ensure they take frequent rest breaks in the shade.

New workers should have a chance to gradually acclimatize to heat, be trained for emergencies and to monitor for heat symptoms.

Employers should also have an emergency plan to respond when someone shows signs of heat-related illness.

OSHA says risk factors for heat illness at work include heavy physical activity, warm or hot environmental conditions, lack of acclimatization and wearing clothing that holds in body heat.

Workers in hot environments indoors or outdoors can be at risk. OSHA says workers have suffered heat-related illnesses in industries including:

  • Warehousing
  • Mail and package delivery
  • Bakeries, kitchens, and laundries (sources with indoor heat-generating appliances)
  • Electrical utilities (particularly boiler rooms)
  • Construction – especially, road, roofing, and other outdoor work
  • Landscaping
  • Agriculture
  • Fire service, and others

During excessive heat at Hartsfield-Jackson International, the world’s busiest airport, officials remind employees of the importance of staying hydrated, wearing appropriate clothing, taking breaks when needed and observing colleagues.

“Situational awareness is vital,” said Hartsfield-Jackson safety manager Nicolas Sotolongo in written comments. “Our employees are taught to prepare for the heat by drinking plenty of fluids before they start work and throughout the day. They are told to maintain vigilance against any signs of heat distress, and they utilize the buddy system and keep any eye on their co-workers to maintain safety.”

OSHA on its website outlines symptoms to keep an eye out for in hot weather. Workers suffering from a heat-related illness may first experience:

  • thirst
  • irritability
  • a rash
  • cramping
  • heat exhaustion

They could also suffer from heat stroke, the most severe form of heat-related illness. Those suffering from heat stroke may experience:

  • confusion
  • disorientation
  • slurred speech
  • unconsciousness

If that happens, the person should be cooled immediately and someone should call 911, OSHA advises.

The agency also says workers can report a complaint to OSHA by calling 800-321-OSHA if they believe their working conditions are unsafe or unhealthful.