Presenter: Michael Miller, Cal/OSHA Consulting

On Thursday May 5 at 8:30am, Safety Center hosted its monthly Safety Forum on the topic of “Heat Illness Prevention” to address the legal obligations of employers to maintain proper work environments during hot weather conditions. During this month’s forum, Michael Miller of Cal/OSHA Consulting discussed this topic and provided insight into Cal/OSHA inspection procedures. Twenty five safety professionals participated in a lively discussion regarding the obligations of employers to prevent heat illness among their employees.

The presentation summary is as follows:

Training Goals:

  • Review the regulatory language and heat illness preventive measures
  • Increase awareness and commitment to safety and health at the worksite

Heat Illness Prevention Elements Include:

  • Access to water
  • Access to shade
  • Weather monitoring and acclimatization
  • High heat procedures
  • Employee and supervisory training
  • Written procedures including emergency response

Access to Water

  • Potable drinking water must be made available at no cost to the employee
  • Maintain, at all times, sufficient quantities of pure and cool potable drinking water, i.e. enough to provide at least one quart per employee per hour for the entire shift
  • Water must be fit to drink. Water containers CANNOT be refilled from non-potable water sources, e.g. irrigation wells, sprinkler or firefighting systems
  • Care must be taken to prevent contamination of the drinking water supplied to the workers
  • Implement and maintain effective replenishment procedures when beginning the shift with smaller quantities
  • Locate the water containers as close as practicable given the working conditions and layout of the worksite
  • Keep it readily accessible, move it with the workers!
  • Encourage the frequent drinking of water

Remind workers not to wait until they are thirsty!

Shade Up: when the temperature exceeds 80 degrees F

  • Have and maintain one or more areas of shade at all times, when employees are present
  • Locate the shade as close as practical to the area where employees are working
  • Provide enough shade to accommodate the number of employees on recovery or rest periods
  • Provide enough shade to accommodate the number of employees on meal period who remain on site
  • Remember: Access to shade must be permitted at all times
  • Encourage employees to take a cool-down rest in the shade
    • Monitor employees on cool down rests
    • Ask them if they’re experiencing symptoms of heat illness
    • Don’t order back to work until symptoms abated allow at least a five minute rest
    • Take appropriate first aid steps or emergency response as necessary
  • Shaded area must not cause exposure to another health or safety hazard. Areas underneath mobile equipment, e.g. tractor, or areas that require crouching in order to sit fully in the shade are not acceptable

If temperature is below 80 degrees F

  • When the temperature does not exceed 80 degrees F, provide timely access to shade upon request

When Infeasible or Unsafe:

  • In situations where the employer can demonstrate that it is not safe or feasible to provide shade, an employer can utilize established procedures for providing shade upon request or, for non-agricultural employers, alternative cooling measures that provide equivalent protection

Monitor the Weather

  • Instruct supervisors to track the weather of the jobsite (by monitoring predicted temperature highs and periodically using a thermometer)
  • Determine, and instruct supervisors, on how weather information will be used to modify work schedule, increase number of water and rest breaks or cease work early if necessary

High Heat Procedures:

  • Industries covered by this subsection:
    • Agriculture
    • Construction
    • Landscaping
    • Oil & Gas Extraction
    • Transportation or delivery of agricultural, construction materials or other heavy materials

When the temperature equals or exceeds 95 degrees F

  • You must implement additional preventive measures:
    • Ensure effective communication (by voice, observation or electronic means)
    • Observe employees for alertness and signs and symptoms of heat illness:
      • Supervisory or designee observation of 20 or fewer employees
      • Mandatory buddy system
      • Regular communication
      • Other effective means
    • Designate one or more employees to call for emergency services
    • Give more frequent reminders to drink plenty of water
    • Hold pre-shift meetings on prevention
    • For agricultural employers
      • Temps 95 or above, ensure employees take a minimum ten minute net prevent cool-down rest every two hours
      • Additional ten minute cool-down rest at end of 8th and 10th hour of work

Emergency Response Procedures

  • Ensure effective communication
  • Respond to signs and symptoms of possible heat illness
    • Supervisor to take immediate, appropriate action
    • If indicators of serious heat illness, implement emergency response procedures
    • Employees exhibiting or reporting signs or symptoms of heat illness shall be monitored and not left alone. Onsite first aid or appropriate emergency medical services shall be offered
    • Contact emergency medical services and ensure that clear and precise directions to the site can be provided

Address Lack of Acclimatization

  • As an employer, you are responsible for the working conditions of your employees, so you must act effectively when conditions result in sudden exposure to heat that your workers are not used to
  • All employees shall be closely observed by a supervisor or designee during heat waves
  • Employees newly assigned to high heat areas shall be closely observed by a supervisor or designee for the first 14 days of employment
  • Thus, determine how your company will:
    • lessen the intensity and/or shift length of newly-hired employee’s work during a two or more week break-in period
    • modify the work schedule or reschedule non-essential duties, during the hot summer months
    • be extra-vigilant with your employees to recognize immediately symptoms of possible heat illness

Employee & Supervisor Training

    • Ensure all employees and supervisors:
      • Are trained before beginning work that should reasonably be anticipated to result in a heat illness
    • The environmental and personal risk factors for heat illness, as well as the added burden of heat load on the body
    • Your company’s heat illness prevention procedures
      • Including, but not limited to, the employer’s responsibility to provide water, shade, cool-down rests, and access to first aid as well as the employees’ right to exercise their rights under this standard without retaliation
    • Importance of frequent consumption of small quantities of water
    • Different types of heat illness, common signs and symptoms; and appropriate first aid or emergency response
    • Knowledge that heat illness may progress rapidly
    • The concept, importance, and methods of acclimatization
    • Training must include the importance of acclimatization, how it is developed, and how your procedures address it.
    • Importance of immediately reporting signs or symptoms of heat illness to a supervisor
    • Procedures for responding to possible heat illness

Procedures to follow when contacting emergency medical services, providing first aid, and if necessary transporting employees

  • Procedures that ensure clear and precise directions to the work site, including designating a person to be available to ensure that emergency procedures are invoked when appropriate


Supervisor Training


  • The heat standard requirements
  • The procedures they must follow to implement the requirements
  • Procedures to follow when a worker exhibits or reports symptoms consistent with possible heat illness, includnig emergency response procedures and first aid
  • How to monitor weather reports and how to respond to hot weather advisories


Written Procedures


  • As long as they are effective, your Heat Illness Procedures can be integrated into your IIPP
  • Maintain the procedures onsite or close to the site, so that it can be made available to employees and representatives of Cal/OSHA upon request
  • Plan in English and the language understood by the majority of the employees
  • Detail how your company will:
    • Provide access to water & shade
    • Monitor the weather
    • Institute high heat procedures
    • Address acclimatization methods and procedures
    • Train all employees and supervisors
    • Respond to heat illnesses without delay, provide first aid and emergency services
    • Provide clear and precise directions to the worksite


Serious Hazard
You risk a serious citation if the outdoor temperature in the work area exceeds 80 degrees F and any of these required elements are not present at the site:

  • Drinking water
  • Shade
  • Trained employees or supervisor
  • Emergency response procedures

Imminent Hazard: Don’t Risk an OPU!
You may also risk an Order Prohibiting Use (OPU) and a Serious Citation if the heat and lack of facilities create an imminent hazard.
An OPU may be issued if:

  • The temperature is > 95 degrees F and water, shade, training or emergency procedures are not in place
  • The temperature is > 80 degrees F, and there is a heat wave, heavy workload or other critical factor putting employees in danger


  • Will shut down the operation
  • Work will not be allowed to resume until the employer demonstrates that the imminent hazard has been corrected

Additional Heat Illness information links:

Multilingual educational materials can be downloaded free from the www.99calor.org website

Share This