WATER. REST. SHADE.
The work can't get done without them.
Protective Measures to Take at Each Risk Level
Drinking Water
Water should have a palatable (pleasant and odor-free) taste and water temperature should be 50°F to 60°F, if possible.
Other Drinks
Encourage workers to choose water over soda and other drinks containing caffeine and high sugar content. These drinks may lead to dehydration. Drinks with some flavoring added may be more palatable to workers and thereby improve hydration. Encourage workers to avoid drinking alcohol after work shifts, during hot weather events.
Use the protective measures described for each risk level to help you plan ahead, and schedule and train your workers so that everyone is prepared to work safely as the heat index rises.
Actions for Low Risk Conditions: Heat Index Less Than 91°F
Actions for Moderate Risk Conditions: Heat Index is 91°F to 103°F
Actions for High Risk Conditions: Heat Index is 103°F to 115°F
Actions for Very High to Extreme Risk Conditions: Heat Index Greater Than 115°F
Summary of Risk Levels and Associated Protective Measures
The most critical actions employers should take to help prevent heat-related illness at each risk level:
Heat Index | Risk Level | Protective Measures |
---|---|---|
<91°F
|
Lower (Caution) |
If workers must wear heavy protective clothing, perform strenuous activity or work in the direct sun, additional precautions are recommended to protect workers from heat-related illness.* |
91°F to 103°F
|
Moderate |
In addition to the steps listed above:
If workers must wear heavy protective clothing, perform strenuous activity or work in the direct sun, additional precautions are recommended to protect workers from heat-related illness.*
|
103°F to 115°F | High |
In addition to the steps listed above:
When possible, reschedule activities to a time when heat index is lower |
>115°F | Very High to Extreme |
Reschedule non-essential activity for days with a reduced heat index or to a time when the heat index is lower Move essential work tasks to the coolest part of the work shift; consider earlier start times, split shifts, or evening and night shifts. Strenuous work tasks and those requiring the use of heavy or non-breathable clothing or impermeable chemical protective clothing should not be conducted when the heat index is at or above 115°F. If essential work must be done, in addition to the steps listed above:
|
*The heat index is a simple tool and a useful guide for employers making decisions about protecting workers in hot weather. It does not account for certain conditions that contribute additional risk, such as physical exertion. Consider taking the steps at the next highest risk level to protect workers from the added risks posed by:
**Under most circumstances, fluid intake should not exceed 6 cups per hour or 12 quarts per day. This makes it particularly important to reduce work rates, reschedule work, or enforce work/rest schedules. |
Contents
- Introduction
- About the Heat Index
- Using the Heat Index to Protect Workers
- Protective Measures to Take at Each Risk Level
Additional Guidance/Resources
Heat Index | Risk Level | Protective Measures |
---|---|---|
Less than 91°F | Lower (Caution) | Basic heat safety and planning |
91°F to 103°F | Moderate | Implement precautions and heighten awareness |
103°F to 115°F | High | Additional precautions to protect workers |
Greater than 115°F | Very High to Extreme | Triggers even more aggressive protective measures |

How can OSHA help? Workers have a right to a safe workplace. If you think your job is unsafe or have questions, visit OSHA's Worker's Page or call 1-800-321-6742 (OSHA). It's confidential. For other valuable worker protection information, such as Workers' Rights, Employer Responsibilities, and other services OSHA offers, visit OSHA's Workers' page.
OSHA also provides help to employers. OSHA's On-site Consultation Program offers free and confidential advice to small and medium-sized businesses in all states across the country, with priority given to high-hazard worksites. For more information or for additional compliance assistance contact OSHA at 1-800-321-6742 (OSHA).