Extreme heat events can cause significant health issues such as heat exhaustion, heat stroke, and other heat stress-related illnesses. Higher temperatures for longer periods can increase the risk of injuries due to fatigue, lack of concentration, and poor decision-making. A reduction in productivity may also occur. [4]

To prevent heat stress, develop and implement a heat stress plan that outlines the measures needed to prevent heat stress, as well as addressing extreme heat events. A heat stress plan may also be part of your emergency preparedness and response plans. The most effective strategies to protect workers are to implement preventive measures and controls to eliminate or minimize a worker's exposure to extreme heat. [1]

The following control measures will help workplaces address heat concerns:

• Do not do physically demanding work in hot environments (e.g., change location or provide air conditioning).
• Improve the ventilation in the building, if needed (e.g., air conditioning, fans, dehumidifiers, etc.).
• Use barriers or insulation to shield workers from equipment that generates heat.
• Provide a cool and shaded area for breaks.
• Ensure workers have access to cool drinking water.

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• Identify which tasks and work areas may be a risk to workers during an extreme heat event.
• Review weather forecasts and pay attention to heat advisories when scheduling work that is done outdoors, is physically demanding, or in indoor spaces that are not temperature controlled.
• Reschedule the work, if possible. If this work can't be rescheduled, make sure workers take breaks, have a cool and shaded area to rest, and drink water often. They should be instructed to immediately stop work and report to their supervisor if they experience any signs of heat stress.
• Provide mechanical aids to reduce the level of physical effort that is required for tasks (e.g., dollies, carts, lifting devices, etc.).
• Schedule physically demanding work for a cooler time of day.
• Rotate workers in and out of areas that are hot or tasks that are physically demanding, when possible.
• Organize work in way that reduces the pace to allow more rest time and time to drink water.
• Assign more workers to a task to reduce the level of effort required by each worker.
• When appropriate and possible, wear personal protective equipment that is light and breathable.

[2] A heat stress plan should:

• Identify when heat stress controls are needed
• Indicate how temperature, humidex, ambient air quality, and other factors that can cause heat stress will be monitored
• Include details on work/rest cycles (e.g., when to shorten work periods and increase rest periods)
• Include heat stress controls specific to your work environment

[2] Address extreme heat events in your emergency preparedness and response plans:

• Supervisors should check-in frequently with workers to identify potential heat stress symptoms
• Have workers present who are trained in first aid and cardiopulmonary resuscitation (CPR). Make sure other workers know who they are and how to contact them.

[2] Develop first aid procedures to assist a person experiencing heat stress. Note that heat stroke is a medical emergency and medical help should be called immediately (911 or local emergency services). Provide first aid until medical helps arrives. [3]

Train supervisors and workers on how to prevent heat stress and how to recognize the signs and symptoms. All workers should know how to respond if heat stress is suspected, and what to do in an emergency. [3]

Workers should:

• Participate in education and training
• Understand the signs and symptoms of heat stress and how to recognize in others. Notify your supervisor immediately if you or your coworkers begin experiencing any signs and symptoms
• Immediately notify your supervisor if you have any health and safety concerns, such as working outdoors in extreme heat or when there is poor ventilation
• Take breaks in cool and shaded areas and drink plenty of water during hot days
• Provide feedback and suggestions to your supervisor or the health and safety committee (or representative) about ways to make your work less physically demanding and more efficient
• When appropriate, wear light and breathable clothing
• Wear sunscreen and protective clothing to prevent sunburns

[3] Heat edema is swelling that generally occurs among people who are not acclimatized to working in hot conditions. The swelling is often most noticeable in the ankles.

Heat rashes are tiny red spots on the skin with severe itching when in a hot, humid environment. The spots are the result of inflammation caused when the ducts of sweat glands become plugged. In most cases heat rash will disappear when the individual returns to a cooler environment. [8]

Heat cramps are painful muscle spasms caused by the body's failure to replace its lost body salts and usually occur after heavy sweating. Heat exhaustion results when the body loses large amounts of fluid by sweating during work in hot environments. The skin becomes cool and clammy. Symptoms include profuse sweating, weakness, dizziness, nausea, and headaches. [9]

Heat stroke is the most serious condition and requires immediate medical attention. The body temperature becomes very high (even exceeding 41°C). Complete or partial loss of consciousness is possible. [9]

Oregon OSHA requires employers to develop and implement a written heat illness prevention rest break schedule that protects employees exposed to a heat index equal to or greater than 90 degrees Fahrenheit. [5]

The heat illness prevention plan must contain information on:

• How employees will be trained on the hazards of heat exposure and the necessary steps to prevent heat-related illnesses
• How to recognize the symptoms of dehydration and how to respond to suspected heat-related illnesses in others
• How sufficient amounts of cool, potable water in work areas will be provided
• How employees will be provided frequent opportunities and encouragement to stay hydrated by drinking water
• How employees will be provided sufficient space to rest in a shaded area or cool climate-controlled area, and where heat-affected employees may cool off and recover when signs and symptoms of heat-related illnesses are recognized
• How the employer will implement the heat illness prevention rest break schedule when necessary to keep employees safe
• How the employer will implement heat acclimatization procedures for new employees or employees returning to work from extended absences of seven or more days.

[6] Training must include:

• The environmental and personal risk factors for heat illness that may limit an individual's tolerance to excessive heat, as well as the added burden of heat load on the body caused by exertion, clothing and personal protective equipment
• The employer's procedures for complying with the requirements of this standard, including, but not limited to, the employer's responsibility to provide water, heat index information (including the risks to experiencing a heat-related illness), shade, preventative rest breaks, and access to first aid, as well as how employees can exercise their rights under this standard without fear of retaliation
• The importance of frequent consumption of small quantities of water, up to 32 ounces per hour, when the work environment is hot and employees are likely to be sweating more than usual in the performance of their duties
• The concept, importance, and methods of the acclimatization plan pursuant to the employer's procedures under section (8)
• The different types of heat illness, the common signs and symptoms of heat illness, and the appropriate first aid and emergency response to the different types of heat illness, including how heat illness may progress quickly from mild signs and symptoms to a serious and life-threatening condition
• The importance for employees to immediately report to the employer, directly or through the employee's supervisor, signs and symptoms of heat illness in themselves or in others
• The effects of nonoccupational factors (drugs, alcohol, obesity, etc.) on tolerance to occupational heat stress.

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