A male Hispanic worker aged 56 died of heat stroke after working for three days hand-harvesting ripe tobacco leaves on a North Carolina farm, according to a report from the National Institute for Occupational Safety and Health (NIOSH). On the third day, the man started working at 6 a.m. and took a short mid-morning break and a 90-minute lunch break. Mid-afternoon, a supervisor observed the man working slowly and reportedly instructed him to rest, but the man continued working.
An hour later, the man appeared confused and coworkers carried him to the shade and tried to get him to drink water. The man was taken by ambulance to an emergency department, where his core temperature was recorded as 108°F and, despite treatment, he died.
On the day of the incident, the local temperature was approximately 93°F with 44 percent relative humidity and clear skies. The heat index (a measurement of how hot it feels when both actual temperature and relative humidity are considered) for the day was in the range of 86–112 F.
Outdoor workers are exposed to two forms of heat stress: internal metabolic (body) heat generated by exertion (hard physical labor) and environmental heat arising from working conditions. Moderate-to-high air temperature, particularly with high humidity; direct sun exposure; heavy or vapor-barrier clothing; and lack of adequate water, rest periods or cooling off conditions all contribute to environmental heat stress and can make exertional heat stress worse.
NIOSH warns that workers of all ages are susceptible to heat-related illness, and their symptoms quickly may become worse after exposure. It is important for outdoor workers to acclimate to local weather conditions, as that may help reduce heat stress effects. Workers who are new to a worksite or returning from an absence of four or more days gradually should increase their work load and heat exposure over a week. When a spike in temperature or a heat wave occurs, workers lose their acclimatization to the environment, and the risk of heat stress increases.
OSHA does not have a specific standard that covers working in hot environments. Nonetheless, under the OSH Act, employers have a duty to protect workers from recognized serious hazards in the workplace, including heat-related hazards.
In 2013, OSHA cited the U.S. Postal Service for a serious safety violation in connection with the heat-related death of letter carrier James Baldassarre, who collapsed on July 5, 2013 after walking his route in Medford, Mass., for about 5 hours in 94-degree heat.
On a day when the heat index exceeded 100 degrees, Baldassarre was carrying a mail bag weighing up to 35 pounds. The area was under a heat advisory from the National Weather Service. He died the next day as a result of heat stroke.
OSHA's investigation found that the U.S. Postal Service exposed workers to the recognized hazard of working in excessive heat by failing to implement an adequate heat stress management program that would have addressed and informed mail carriers of how to identify, prevent and report symptoms of heat-related illnesses.
"As we move into the summer months, it is very important for workers and employers to take the steps necessary to stay safe in extreme heat," said OSHA Assistant Secretary Dr. David Michaels. "Drinking water often, taking breaks and limiting time in the heat are simple, effective ways to prevent heat illness."
Prevention is the best way to avoid heat-related illness. Employers, field supervisors and workers should follow the recommendations from NIOSH below to reduce the risk of heat-related illness in outdoor workers. NIOSH recommends that employers establish a heat-related illness prevention program that includes the following measures:
- Training for supervisors and workers to prevent, recognize and treat heat-related illness.
- Implementing a heat acclimatization program for workers.
- Providing for and encouraging proper hydration with proper amounts and types of fluids.
- Establishing work/rest schedules appropriate for the current heat stress conditions (an industrial hygienist may need to be consulted).
- Ensuring access to shade or cool areas.
- Monitoring workers during hot conditions.
- Providing prompt medical attention to workers who show signs of heat-related illness.
- Evaluating work practices continually to reduce exertion and environmental heat stress.
- Monitoring weather reports daily and rescheduling jobs with high heat exposure to cooler times of the day.