The risk of heat-related illness becomes greater as the weather gets hotter and more humid. Late Spring and early Summer when hot weather arrives early can be deadly because workers have not had a chance to adapt to warm weather. So, now is the time to climatize.

Your weatherman is beginning to talk of the “heat index.” Heat index is the is a single value that takes both temperature and humidity into account. The higher the heat index, the hotter the weather feels since sweat does not readily evaporate and cool the skin.

Heat Illness

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. Workers performing strenuous activity, workers using heavy or non-breathable protective clothing, and workers who are new to an outdoor job need additional precautions beyond those warranted by heat index alone. Due to the pandemic warnings, some are also required to wear face covering which also add to the heat.

Workers new to outdoor jobs or those with other illnesses and medications are generally most at risk for heat-related illnesses.

Time to Acclimate

That is why it is important to gradually increase the workload or allow more frequent breaks to help new workers and those returning to a job after time away build up a tolerance for hot conditions. Make sure that workers understand the risks and are “acclimatized”.

Steps to Take

• Remind workers to drink water often (about 4 cups/hour)**
• Review heat-related illness topics with workers: how to recognize heat-related illness, how to prevent it, and what to do if someone gets sick
• Schedule frequent breaks in a cool, shaded area
• Acclimatize workers
• Set up buddy system/instruct supervisors to watch workers for signs of heat-related illness

Once the heat index gets too high, you must:

• Alert workers of high-risk conditions
• Actively encourage workers to drink plenty of water (about 4 cups/hour)**
• Limit physical exertion (e.g. use mechanical lifts)
• Have a knowledgeable person at the worksite who is well-informed about heat-related illness and able to determine appropriate work/rest schedules
• Establish and enforce work/rest schedules
• Adjust work activities (e.g., reschedule work, pace/rotate jobs)
• Use cooling techniques
• If possible, reschedule some activities to a time when the heat index is lower

It is best to move essential work tasks to the coolest part of the work shift and consider earlier start times, split shifts, or evening and night shifts.