Epidemiology: Occupational and Environmental

Heat exposure in the workplace is a concern for many occupations, including both outdoor and indoor workers.

Outdoor workers at risk include:

• Construction
• Farmworkers
• Landscaping
• Mail and package delivery
• Oil and gas well operations

Indoor workers at risk include:

• Bakeries, kitchens, laundries
• Electrical utilities (particularly boiler rooms)
• Fire Service
• Iron and steel mills and foundries
• Manufacturing with hot local heat sources
• Warehousing

Excess heat exposure in the workplace can result In:

• Heat rash
• Heat cramps
• Heat fainting
• Heat exhaustion
• Heat stroke

Heat index is often used to measure heat exposure. Heat index is a measure of how hot it “actually feels”. The heat index increases with temperature and humidity. This means that it can feel hotter when it is also humid.

Heat index alone is not enough to measure the risk of heat exposure to workers. We must also look at other factors like level of exertion and duration of activity, hydration, sources of direct heat, health condition, physical fitness, acclimatization.

Heat-related illnesses can be prevented. Prevention requires employers and workers to recognize heat hazards. Employers may need to:

• Train supervisors and workers to control and recognize heat
• Implement engineering and administrative controls to reduce heat
• Provide sufficient rest, shade, and
• Determine, for each worker throughout each workday, whether total heat stress is too high, both from the conditions of that day and potential carryover effects. A "carryover effect" means that the worker’s body temperature could continue to heat up even after being removed from a hot environment.
• Take extra precautions to protect new

More information about these preventive measures is available by exploring the following links on OSHA’s website:

www.osha.gov/heat-exposure/prevention
www.osha.gov/heat-exposure

• Call 911 for immediate medical
• Never leave a worker with heat-related illness The illness can rapidly become worse. Stay with the worker.
• Stop working, get cool, get shade, and drink fluids
• Symptoms can occur in any order. You don't need to have all of the symptoms in a category to have heat illness

Illnesses caused by heat	Signs and Symptoms	What to do
Heat Rash	Red cluster of pimples or small blisters	Move to cooler, less humid areas Keep rash area dry; do not use ointments or creams
Heat Cramps	Muscle cramps, pain, or spasms in abdomen, arms, or legs	Drink fluids Get medical help
Heat Fainting	Fainting, dizziness Light-headedness after standing or suddenly rising from a sitting/lying	Sit or lie down in a cool place Slowly drink water or clear juice
Heat Exhaustion	Headache, nausea, dizziness, weakness, thirst, heavy sweating, irritability	Get medical help Remove from hot area and give frequent sips of liquids Cool worker with cold compresses, ice bath, fans
Heat Stroke	Confusion, altered mental state slurred speech, loss of consciousness hot, dry skin seizures	MEDICAL EMERGENCY - get medical help immediately Move to cool place Remove clothing and immerse in tub of ice water (or place in tarp with ice) or apply cold wet towers to entire body
Table source: NIOSH First Aid for Heat Illness Fact Sheet

OSHA has proposed a rule currently titled Heat Injury and Illness Prevention in Outdoor and Indoor Work Settings. In summary, the proposed rule would require employers to develop an injury and illness prevention plan to control heat hazards in workplaces affected by excessive heat. Among other things, the plan would require employers to evaluate heat risks and — when heat risks increase — implement requirements for drinking water, rest breaks and control of indoor heat. It would also require a plan to protect new or returning workers unaccustomed to working in high heat conditions. Employers would also be required to provide training, have procedures to respond if a worker is experiencing signs and symptoms of a heat-related illness, and take immediate action to help a worker experiencing signs and symptoms of a heat emergency.

This OSHA proposed rule has not yet been finalized.

Before finalization, OSHA has to collect public comments, respond to all comments, and then develop a final rule.