We're sorry, but OSHAcademy doesn't work properly without JavaScript enabled. Please turn on JavaScript or install a browser that supports Javascript.

645 Heat Injury and Illness Prevention: Employee Skip to main content

645 Heat Injury and Illness Prevention: Employee

Colorado Requirements

Image of the flag of the state of Colorado.

Application & Scope

This section supplements OSHAcademy Course 645: Heat Injury and Illness Prevention (Employee) and is designed to align the training with the Colorado Department of Labor and Employment (CDLE) heat illness and Injury Protection Rule. For more in-depth review or questions about the Rule please click on the link below:

The Colorado standard establishes mandatory protections for agricultural workers who are exposed to environmental heat, whether working outdoors or in enclosed structures such as greenhouses, barns, and packing facilities. It is one of the first comprehensive heat protection standards for agricultural employees.

When the Rule Applies

The heat rule applies on any day the worksite temperature is or is forecast to be ≥ 80°F. There are narrow exceptions for very brief exposures and timing; to view the exceptions you may review 7 CCR 1103-15.

For outdoor work, employers may rely on a forecast high from a reliable source (from no earlier than noon the prior day). For indoor ag work, the employer must measure the worksite temperature during the workday and apply the rule when the measured or reasonably expected temperature meets the ≥ 80°F threshold and/or the ≥ 95°F increased risk threshold.

The rule does not apply where:

  • An employee's exposure above the threshold is 15 minutes or less in any 60-minute period
  • Forecasts/actuals show the threshold is reached only outside the hours employees work

For range workers or other situations where temperatures can't reliably be measured or communicated, employers may use prior-year monthly average high temperatures (≥ 76°F for baseline heat protections; ≥ 90°F for increased risk conditions).

Drinking Water

Employers must provide potable water:

  • At ≥ 32 oz per worker per hour, kept 60°F or cooler.
  • From a sanitary source, readily accessible during shifts and breaks.
  • Located as close as practicable to the worksite and no farther than 0.25 miles on foot (or otherwise reasonably accessible).

Employers must allow employees time during shifts to drink water and use restrooms as needed.

For range or ranch workers who spend most of the day mobile and far from a water source, employers must comply to the maximum extent possible, including re-supplying water when visiting nearby locations and providing equipment so workers can carry or safely obtain potable water (e.g., purification containers)

Shade / Cool-Down Areas

Employers must provide:

  • Adequate shade (natural or artificial) as close as practicable to the worksite and no farther than 0.25 miles on foot
  • It must be ventilated/open
  • Large enough for workers to sit without crowding
  • Free of added heat sources (e.g., running vehicles)
  • free of unsafe, unhealthy, or unsanitary conditions (for example, strong odors from rot or garbage) that would discourage workers from using it
  • Range workers must be allowed to seek and use shade during rest and meal periods to limit heat and sun exposure
  • Alternatives (e.g., A/C spaces or individual cooling items) are required if shade can’t be safely provided

Increased Risk Conditions (Extra Protections)

On days with increased risk conditions, employers must add protections. What triggers "increased risk":

  • ≥ 95°F forecast or measured at the worksite
  • Air quality advisory/action day (with limited ozone exception)
  • Employees working longer than 12 hours in a single day
  • Employees are required to wear heavy/vapor-barrier PPE
  • New employees or employees working in the heat for the first time in over a month must be acclimatized during their first four days.

What's required under increased risk:

  • Ensure no more than 2 hours of work occur before at least 10 minutes of rest are provided, by spacing existing or adding breaks (range workers: encourage 2-hour spacing to the maximum extent possible).
  • Notify employees before the shift (or ASAP) of all heat protections and their right to preventive cool-down rests.
  • If ≥ 95°F is reasonably expected/occurs at any point in the year, fans/air circulation must be provided in employer-provided sleeping quarters.

Safety Procedures

Communication: Maintain effective two-way communication (voice/observation/electronic) so workers can reach supervisors or EMS; if reception is unreliable (e.g., range work), implement alternative methods (scheduled check-ins, satellite/ radio, etc.).

Monitoring: Use designated observers (≤ 20 workers each), a buddy system, regular check-ins for lone workers, or other effective means to monitor/report heat symptoms.

If a worker is exhibiting symptoms of heat illness:

  • Promptly relieve symptomatic workers; monitor and ensure they are not left alone or sent home without first aid/EMS offer as appropriate.
  • Emergency response: designate person(s) to call EMS, provide site directions, and arrange transport if needed.
  • Preventive cool-down rest: may not be denied or delayed; may coincede with existing rest or meal periods; monitor during rest, ask about symptoms, and do not return to work until symptoms abate — but never less than 10 minutes after reaching shade.

Training

If ≥ 80°F is reasonably expected at any point in the year, employers must train all employees by April 20 each year and upon hire. Training must cover:

  • Environmental/personal risk factors, acclimatization, hydration, symptom recognition/progression, basic first aid, emergency responses, employee's rights, prohibition of employer retaliation and the requirements of Rule 3 — including how the employer is providing water, shade, and break time.
  • Supervisors must be trained on their assigned roles.
  • Primary-language access is required for non-English-fluent employees (written or verbal).

Employers may use recognized heat-safety programs (such as OSHA's Heat Illness Prevention Training Guide, the University of Washington’s HEAT toolkit, or UC Davis Western Center materials) or similar programs to meet the training content requirements.

Documentation & Notice

  • Employers must implement and communicate the Rule 3 program elements (water, shade, breaks, monitoring, emergency response, training).
  • Separate sections of 7 CCR 1103-15 (Rule 5) require posting a notice of rights and prohibit retaliation or interference with workers who report hazards, seek water/shade/rest, or use other protections under Rule 3.

Knowledge Check Choose the best answer for the question.

9-Colorado. What is the minimum temperature at which the Colorado heat rule applies to agricultural work?

Back