When employees are exposed to work conditions that may present a hazard due to extreme heat, employers have several responsibilities [1] [2]:

• Monitoring Thermal Conditions: A competent person must measure and record thermal conditions at frequent intervals and make the findings available to a committee, if any, and to an officer on request [1].
• Following Exposure Limits: Occupational exposure limits for protection against heat stress must be followed, including work-rest regimens [1].
• Training: Employers must ensure employees are trained by a competent person in the significance of heat stress symptoms (e.g., heat exhaustion, dehydration, heat cramps, heat stroke) and precautions to avoid injury [2].
• Drinking Water: Ensure a sufficient supply of drinking water is readily available to exposed employees at all times, at no cost, when the heat index in the work area equals or exceeds 80 degrees Fahrenheit [3]. Supply each employee with enough drinking water to enable them to consume up to 32 ounces per hour [3].
• Access to Shade: Establish and maintain one or more shade areas that are immediately and readily available to exposed employees that are outdoors when the heat index in the work area equals or exceeds 80 degrees Fahrenheit [4].
• High-Heat Practices: When engineering and administrative controls do not reduce an employee's exposure to a heat index of less than 90 degrees Fahrenheit, implement and maintain high-heat practices and procedures [3].
• Rest Break Schedule: 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].

It's also important to be aware of workload classifications (light, moderate, heavy, very heavy) to understand metabolic heat generation [6].