Protecting Workers from Indoor and Outdoor Heat Exposure

Heat illnesses affect workers in a range of indoor and outdoor occupations, including agriculture, landscaping, construction, airport baggage handling, mining, firefighting, bakeries, factories, commercial kitchens, and more. According to the U.S. Department of Labor:

• Millions of U.S. workers are exposed to heat in their workplaces.
• Heat-related illness is preventable, yet thousands of workers become sick from occupational heat exposure every year, and some cases are fatal.
• Most outdoor fatalities, 50% to 70%, occur in the first few days of working in warm or hot environments because the body needs to build a tolerance to the heat gradually over time. The process of building tolerance is called heat acclimatization. Lack of acclimatization represents a major risk factor for fatal outcomes.

Heat Illness Symptoms and Treatment

As with other safety threats in the workplace, heat-related illnesses can be prevented, but it is important to be aware of the symptoms and first-aid measures to take if necessary. Here is a brief outline of the symptoms and recommended first aid treatment for heat-related illnesses.

Heat rash is the most common heat-related problem in the workplace. It appears as clusters of red bumps on the skin, most often on the neck, upper chest, and folds of skin. If affected by heat rash, keep the affected area dry and try to work in a cooler, less-humid environment.

Heat cramps are muscle spasms and pain, usually in the abdomen, arms, or legs. A worker who is experiencing heat cramps should rest in a shady, cool area and drink plenty of water. The worker should rest for a few hours before returning to strenuous work activity. Medical attention is advised if the cramps do not go away within one hour or so.

Heat exhaustion symptoms include cool, moist skin and heavy sweating, as well as headache, nausea or vomiting, dizziness, lightheadedness, weakness, thirst, irritability, and fast heartbeat. This is serious enough that if a worker experiences heat exhaustion they should not return to work for the remainder of the day. The affected worker should sit or lie down in a cool, shady area and drink plenty of water. The worker can also be cooled by using cold compresses or ice packs. If the signs or symptoms worsen or do not improve within 60 minutes, the worker should be taken to a clinic or emergency room for evaluation and treatment.

Heat stroke is a medical emergency – call 911 immediately. Symptoms may include confusion, fainting, seizures, and a very high body temperature. The individual may be sweating excessively, or their skin may be red, hot, and dry. While waiting for medical help, move the worker to a cool area and give them fluids – preferably water. Loosen their clothing and remove outer clothing. If available, apply ice packs, cool compresses, or ice. Do not leave them alone while waiting for help.

Building a Heat Illness Prevention Plan

Employers have a responsibility under OSHA law to provide a workplace free from recognized hazards, including extreme heat hazards. A heat illness prevention plan can help employers respond before conditions become dangerous.

A strong plan should include the following practices:

Provide water, rest, and shade. Employees should have access to drinking water throughout the workday. Encourage employees to drink water frequently instead of waiting until they feel thirsty. Rest areas should be shaded, air-conditioned, or otherwise cooled when possible.

Help employees build heat tolerance. New and returning employees need time to adjust to hot conditions. Gradually increasing workloads and allowing more frequent breaks during the first days of heat exposure can help employees build tolerance and reduce risk.

Train employees and supervisors. Training should cover heat illness symptoms, prevention practices, emergency response procedures, and the importance of reporting symptoms early.

Monitor conditions and employees. Employers should monitor heat levels, humidity, workload, and employee condition. Employees who work alone or in high-heat environments should have a clear way to communicate if symptoms develop.

Plan for emergencies. Every heat illness prevention plan should include clear emergency procedures, including who to contact, when to call 911, where cooling supplies are located, and how to guide emergency responders to the worksite.

Review job tasks and schedules. When possible, schedule physically demanding tasks during cooler parts of the day. Adjust work/rest cycles during periods of high heat and consider whether additional staffing, task rotation, or temporary changes are needed.

Heat Risk Isn’t Limited to Outdoor Work

• Install and maintain adequate air conditioning and cooling fans.
• Increase general ventilation to help circulate cooler air.
• Ensure that points of high heat production or moisture have local exhaust ventilation.
• Install reflective shields to redirect radiant heat and make sure hot surfaces (such as furnace walls) are insulated.
• Watch for and eliminate all steam leaks.
• Establish an emergency plan that includes how to recognize the signs of heat-related illness and appropriate treatment methods. Make sure employees are familiar with the plan.
• Acclimatize workers to warmer work conditions by gradually increasing workloads and allowing more frequent breaks during the first week of work.
• Provide plenty of drinking water close to the work area, and encourage employees to drink water frequently throughout the day.
• If possible, schedule heavier work for cooler times of day, and rotate job functions to minimize overexertion and exposure to heat.
• When appropriate to the job situation, provide personal protective equipment (e.g., respirators, insulated gloves, and impermeable clothing).