Dept. of Industrial Relations logo

Heat Illness Prevention enforcement Q&A

Effective Date: 04 November 2010

Introduction: This document has been updated to incorporate the regulatory changes that went into effect on November 04, 2010 and is intended to serve two purposes. The first is as an instruction and interpretive document on DOSH policy for DOSH enforcement and consultation personnel. The second is as a service to employers and employees to make it known how DOSH interprets and enforces the standard. A supplemental Q&A regarding heat illness prevention for amusement ride employees:

1. Where and when does this standard apply?

This standard applies in all outdoor places of employment. In addition, the following industries have additional requirements (see Q&A No. 11b):

  1. Agriculture,
  2. Construction,
  3. Landscaping,
  4. Oil and gas extraction and
  5. Transportation and delivery of agricultural products, construction or other heavy materials (e.g. furniture, lumber, freight, cargo, cabinets, industrial or commercial materials).

DOSH interprets the standard's provisions to apply at all times when employees are at work outdoors. However, special provisions apply to enforcement of the shade requirement, as described in Q&A No. 7, to the training requirements, as described in Q&A No.12, and to High Heat Procedures in Q&A No. 11b.

2. What is meant by outdoor places of employment?

An outdoor place of employment is best thought of as one that is not an indoor workplace. A workplace with a roof and enclosed sides is generally considered an indoor workplace.

For the purposes of this standard, the important quality of the majority of indoor workplaces is that they reduce the risk factors that commonly lead to heat illness. (For information about environmental risk factors for heat illness, see Q&A Nos. 4 and 5.) For example, building codes require that buildings provide sufficient ventilation, either by natural or mechanical means. Indoor workplaces usually also block exposure to direct sunlight.

On the other hand, open areas like agricultural fields, forests, parks, equipment and storage yards, outdoor utility installations, tarmacs, and roads, are obvious examples of outdoor workplaces. Outdoor workplaces also include construction sites in which no building shell has been completed and areas of construction sites that are outside of any building shells that may be present. Outdoor areas adjacent to buildings, e.g., loading docks, are also considered outdoor places of employment if an employee spends a significant amount of time working in them.

Sheds, packing sheds, and partial or temporary structures such as tents, lean-tos, and structures with one or more open sides can be either indoor or outdoor workplaces depending on the circumstances. In many cases these structures may actually be hotter than the environment outside of them because of heating by the sun and conditions inside like limited air circulation or lack of insulation. DOSH considers a structure in this category to be an outdoor workplace if it does not significantly reduce the net effect of the environmental risk factors that exist immediately outside of the structure.

3. Are there other regulations that apply to the risk of heat illness?

Yes. They include requirements for employers to have an effective Injury and Illness Prevention Program and to provide for drinking water, first aid and emergency response. There are also requirements tailored to specific industrial operations.

IIPP. Title 8 CCR 3203 requires an employer to establish, implement, and maintain an effective Injury and Illness Prevention Program. All IIPPs must include effective procedures for hazard identification, evaluation and control, hazard correction, investigation of employee injuries and illnesses, and communication with employees about health and safety matters.

The requirement for effective communication is particularly relevant to heat-illness prevention. In evaluating compliance with this requirement, DOSH determines what the employer does to account for the whereabouts of all employees at appropriate intervals during the work shift and at the end of the shift. This is a critical procedure to follow when the outdoor work environment creates a heat hazard that could result in the collapse of an employee due to heat illness. Indoor heat can be a known hazard in the workplace, and under the obligation of the IIPP, employers are required to inform their employees about the hazard and outline the steps taken to mitigate it.

Drinking Water. The following Title 8 standards apply to the provision of drinking water:

  • Construction 8 CCR 1524
  • Hand labor in agriculture 8 CCR 3457
  • Mining 8 CCR 6975
  • All other places of employment 8 CCR 3363

These standards require provision of sufficient quantities of drinking water in general in any work environment to which they apply. For employees working in the heat, a minimum of one quart of drinking water per hour must be available to each employee, e.g., two gallons per employee for an eight-hour shift, to replace water lost by sweating.

First Aid and Emergency Response. The following Title 8 standards apply to the provision of first aid and emergency response:

  • Construction 8 CCR 1512
  • Agriculture 8 CCR 3439
  • Logging and sawmills 8 CCR 6251
  • Petroleum drilling and production 8 CCR 6511-6512
  • Petroleum refining, transportation and handling 8 CCR 6767
  • Tunneling 8 CCR 8420-8421
  • Telecommunications 8 CCR 8602(e)
  • All other places of employment 8 CCR 3400

Heat and Temperature. The following standards apply to heat stress or temperature control in specific operations:

  • Hazardous waste sites and emergency response 8 CCR 5192
  • Working chambers subjected to compressed air 8 CCR 1230(a)
  • Ventilation. Building ventilation systems are regulated by 8 CCR 5142 and 8 CCR 5143.

4. What are the environmental risk factors for heat illness?

Section 3395 defines environmental risk factors as including "air temperature, relative humidity, radiant heat from the sun and other sources, conductive heat sources such as the ground, air movement, workload severity and duration, protective clothing and personal protective equipment worn by employees."

Some of these factors, such as air temperature, radiant heat, air movement and conductive heat sources determine how much an employee's body is heated from external sources. Relative humidity, air movement, protective clothing, and some personal protective equipment affect an employee's ability to cool through the evaporation of sweat and contact with cooler air. Workload intensity and duration, which can be increased by use of personal protective equipment, add to the employee's heat burden by producing metabolic heat. 

It is essential, through training, that supervisors and workers understand how environmental and personal risk factors, as well as the added burden of heat load on the body caused by exertion, clothing and personal protective equipment, can increase the risk of heat illness.

5. How can you monitor the weather and evaluate the severity of environmental risk factors for heat illness?

It is critical that employers track the weather and routinely check for approaching heat waves. Heat waves are the primary cause of heat-related illnesses and fatalities in the state. For example, according to a study by Cal/OSHA, 84% of the heat illnesses in 2006 occurred during the July heat wave.

This study also identified the key role that supervisors hold in preventing worker fatalities due to heat illness. This highlights the value of training supervisors so that they can make the fullest use of their supervisory power to control safety on the job.   Knowing how to monitor weather reports, making it a daily practice of doing so, and taking appropriate action in response to predicted hot weather is an essential part of a supervisor’s training, and it is essential that this training be provided to all supervisors.  Although the standard has no specific requirement on how to respond, it is up to employers to make their best judgment on what to instruct supervisors to do in reaction to hot weather advisories.   

The National Weather Service forecasts the temperature in various locations in California. Weather forecasts and information are broadcast on NOAA Weather radio and can be accessed at:

The supervisor should use a thermometer to keep track of the temperature at the worksite on hot days. A simple thermometer like those available at hardware stores, can be used to measure the outdoor ("dry bulb") temperature, as long as it is taken in an area where there is no shade. The temperature measurement must be taken in an area with full sunlight and the bulb or sensor of the thermometer should be shielded from direct contact with sunlight (with the hand or some other object), while taking the measurement.

Employees who use chemical protective clothing such as hazmat suits designed to be impervious to chemical liquids and vapors, or other clothing or body coverings that significantly interfere with the body's ability to dissipate heat compared with normal clothing, can be at risk of heat illness even when temperatures are considered mild. These employees should be included in a heat illness prevention program.

6. What is considered sufficient access to drinking water?

Adequate water is required at all times, regardless of outdoor temperature and must be made available at no cost to the employee.

Water Quality and Amount: Potable drinking water must always be placed in locations readily accessible to all employees. The water provided must be fresh and pure, suitably cool, and in sufficient amounts, taking into account the air temperature, humidity, and the nature of the work performed, to meet the needs of all employees.

Water must be fit to drink. Water containers must be filled directly from a potable water supply. Water containers CAN NOT be refilled from non-potable water sources (i.e. sprinkler or firefighting systems), or connections that allow for potentially harmful contamination of public water systems (i.e. water hose) or from non-approved or non-tested water sources (i.e. untested-wells).

Where unlimited drinking water is not immediately available from a plumbed system or otherwise continuously supplied, the employer must provide enough water for every employee to be able to drink one quart of water, or four 8-ounce cups, per hour. The water must always be cool, and in very hot weather it is recommended that employers have ice on hand to keep the water cool.

If an employer chooses not to provide the full-shift quantity of drinking water at the start of a work shift (e.g., 2 gallons per employee for an 8-hour shift), the standard requires effective procedures for drinking-water replenishment to allow each employee to drink one quart per hour. This means a sufficient quantity of water must always be present and readily accessible to allow every employee to consume at least one quart of water per hour until such time that the water supply has been replenished.

A water-supply procedure that depends on replenishment during the work shift is out of compliance if it is not reliable. An employer is also out of compliance if at any time drinking water is not available to employees, or if the practice is to wait until the water vessel is empty to replenish it. It is similarly impermissible for an employer to replenish the drinking-water supply only when requested by employees.

Distance: Water must always be readily accessible. DOSH interprets this phrase to mean that the water should be as close to the employee as is practicable, given the working conditions and layout of the worksite. On inspection, if a DOSH inspector questions whether the water supply is close enough to the employees, he or she will ask the supervisor present to explain the factors taken into consideration by the employer in determining the placement of water. DOSH must by law accept placement of the water at a distance that is reasonable under the circumstances.

Employers should build their water placement strategies around a sound understanding of the fact that the more an employee has to interrupt work in order to drink, the greater will be the likelihood that the employee will not be drinking as much water as is necessary to protect fully against heat illness. An employer may choose to augment an existing water supply that is compliant and readily accessible by providing a beverage container (preferably insulated) to be carried and used by the employee while working. The employee must be encouraged to refill the container from the employer's drinking-water supply, and clean and maintain it as needed.

Why water is so important: Water is the body's single best defense against heat other than removing heat exposure itself. In conditions of high heat and strenuous work, the human body can lose over a quart of fluid per hour just by sweating. Continuous replacement of this lost fluid is critical to allowing the body to maintain the life-preserving cooling benefits of perspiration. This is why assuring the presence of, ready access to, and consumption of pure, fresh, and cool drinking water is so important.

Encouragement to drink water: The standard requires not only that water be provided, but that employers encourage employees to drink it frequently. The importance of this cannot be overstated. Employees are there to work, and many of them may not feel how urgently their bodies need water. This is an unfortunate but preventable cause of heat illness.

Employers must emphasize this in their training sessions and stress the importance of frequent drinking of water throughout the day, especially in high heat. This can be significantly facilitated by steps such as removing any barriers that may exist to access, making the access distance as short as reasonable, and making the water station inviting by using ice and shade.

The 2006 Cal/OSHA Heat Illness Case Study showed that although 90% of the worksites had drinking water at the site, 96% of the employees suffering from heat illnesses were dehydrated.

Water temperature and use of ice: When temperatures exceed 90 degrees F, having ice on hand to cool the water is recommended. Cool water adds the extra benefit of providing direct cooling to the body immediately upon consumption, independent of perspiration.  However, care must be taken to ensure that water is not too cold as to discourage workers from drinking it.

7a. What is considered sufficient access to shade?

When the actual presence of shade is required.: The heat illness prevention standard requires that employers have and maintain one or more areas with shade at all times while employees are present, when the outdoor temperature exceeds 85 degrees Fahrenheit.   It is always advisable to have shade present even when temperatures do not exceed 85 degrees, if the weather is hot enough to make shade a useful tool for cooling off.

The shaded area(s) must be either open to the air or provided with ventilation or cooling.  The amount of shade present shall be at least enough to accommodate 25% of the employees on the shift at any time, so that they can sit in a normal posture fully in the shade without having to be in physical contact with each other. 

When the temperature does not exceed 85 degrees Fahrenheit, employers must provide prompt access to shade when requested by an employee.

Employers should monitor predicted weather temperatures in advance, for example via TV or radio, so that they can have a general idea when the temperature is likely to exceed 85 degrees.

Regardless of what the predicted high has been the previous day, employers are expected to know if the actual temperature is exceeding 90 degrees F at their worksite. If the temperature enters this range, shade must actually be present regardless of the previous day's predicted temperature high.

Quality: Shade is blockage of direct sunlight. Blockage is always sufficient when objects do not cast a shadow in the shaded area. An enclosed area used to provide shade must allow cooling at least comparable to the cooling that would be provided in a shaded unenclosed area in the same location.

Sources: Shade may be provided by any natural or artificial means that do not expose employees to unsafe or unhealthy conditions. 

For example, shade can be provided by buildings, canopies, lean-tos, or other partial or temporary structures that are either ventilated or open to air movement. Trees and dense vines can provide shade that is superior to artificially provided shade and are accepted as compliant sources of shade if the following conditions are met.  First, that the canopy of the trees or vines must be sufficiently dense to provide substantially complete blockage of direct sunlight. Second that the vines or branches from the trees must not be so low to the ground that employees must crouch or cannot sit up straight without contacting vegetation.

Flecks of sunlight are acceptable as long as, overall, the shade provides substantially complete blockage of sunlight. Where trees or other vegetation are used to provide shade, the thickness and shape of the canopy must, given the changing angles of the sun, result in a sufficient shadow being cast to protect employees from the sun during the entire shift.

The interior of a vehicle may not be used to provide shade unless the vehicle is air-conditioned and the air conditioner is operating. Similarly, metal storage sheds and other out-buildings do not provide protection from sunlight that meets the definition of shade unless they provide a cooling environment comparable to shade in open air (i.e., they must be mechanically ventilated or open to air movement).

Conditions of Access: The shaded area must let employees assume a comfortable posture and must not cause exposure to another health or safety hazard. Therefore, the shade requirement cannot be met by using areas underneath mobile equipment, like a tractor, or areas that require employees to crouch in order to sit fully in the shade.

7b. How much shade must be available?

The amount of shade present shall be at least enough to accommodate 25% of the employees on the shift at any time, so that employees can sit comfortably and fully in the shade without touching each other. 

During the shift, there must always be enough shade to accommodate those employees who seek it to cool off as required by the standard. Employers should anticipate that the hotter the weather gets, the more employees are likely to seek shade at the same time. This does not mean there must be enough shade to accommodate all employees on the shift at the same time, however. Rather, an employer may comply by adopting a procedure to ensure that employees who desire access to shade will not be deprived of it due to lack of space. One such procedure would be for the rotation of employees in and out of shaded areas to ensure all have sufficient access for the five-minute interval specified in the standard. Another would be to set up additional shade structures as needed.  Any such procedure must be clearly and accurately described employer's written heat illness prevention procedures.

7c. How close must a shaded area be to employees?

The shade must be close enough to accomplish the fundamental purpose of the standard, which is to provide reasonable access to shade as dictated by the need for cooling the body in hot weather.  What is reasonable depends on the nature and circumstances of the work and how much heat load the weather and the work are placing on the body.  As the weather becomes critically hot, the more critical it becomes to ensure ready access to shade and water without delay.  The shaded area must be as close as practical to the area where employees are working, but no more than a 2.5 minute walk away.  The hotter the weather, the closer the shade or shade structure needs to be to the workers.

Note: The time it realistically takes to get to the shaded area is the critical consideration, and this will be taken into consideration if the means of access is by vehicle instead of walking.

8a. What if it is unsafe to provide a shade structure?

When the employer can demonstrate that a shade structure would be unsafe or infeasible, then the employer may provide alternate access to shade that provides equivalent protection, if:

Erecting shade is problematic such as near the edge of a trench or ravine, or when high winds won’t allow a shade structure to be opened or to be placed near workers without risking it flying away and hitting them; or establishing a shade structure on a continuous basis is infeasible due to employees constantly moving from site to site (i.e. meter readers or irrigation installers.)  In these cases the employer must document this determination  and specify what alternatives to shade will be provided which afford equivalent protection.

8b. When may employers use cooling measures other than shade?

Non-agricultural employers may provide cooling measures other than shade, if they can demonstrate that the alternative is at least as effective as shade.

For example, misting machines are acceptable when the employer can demonstrate that they are at least as effective as shade at allowing the body to cool.

9. What are the requirements for encouraging workers to rest in the shade?

The employer is required to allow and encourage employees to take a cool-down rest in the shade for a period of no less than five minutes at a time when they feel the need to do so to protect themselves from overheating. The purpose of the cool-down rest in the shade is to reduce heat stress on the employee. Shade removes sunlight as a source of heat, and since people produce more metabolic heat while working, resting reduces this as a source of heat stress, while also reducing the heart rate. Cool, fresh water should be available in the recovery area to encourage employees to drink it.

Encouraging employees to take a cool-down rest in the shade is of primary importance particularly for employees that are paid on a piece rate basis, as they would be less inclined to use this preventive rest.

Access to shade must be allowed at all times, and the employee must be allowed to remain in the shade for at least five minutes. The importance of prevention cannot be overstated. By waiting until symptoms appear before seeking shade and recovery, employees are at significant risk of developing serious heat illness, and the preventative purpose of the standard is defeated. When employees opt to access shade, employers should use this as an opportunity to encourage them to drink as much water as they comfortably can.

The cool-down rest in the shade is not a substitute for medical treatment. If an employee has any symptoms of heat illness, first-aid procedures should be initiated without delay. Common early signs and symptoms of heat illness include headache, muscle cramps, and unusual fatigue. However, progression to more serious illness can be rapid, and can include loss of consciousness, seizures, mental confusion, unusual behavior, nausea or vomiting, hot dry skin, or unusually profuse sweating.

Any of these symptoms requires immediate attention. Even the initial symptoms may indicate serious heat exposure. If medical personnel are not immediately available onsite and serious heat illness is suspected, emergency medical personnel should be immediately contacted and on-site first aid undertaken. No employee with symptoms of possible serious heat illness should be left unattended or sent home without medical assessment and authorization.

10. What written procedures should an employer develop to comply with the requirements of this standard?

It is up to the employer to develop, put in writing, and implement effective procedures for complying with the requirements of this standard, comprising of:

  • procedures for water replenishment during the shift as needed,
  • employee access to shade and how employees will be encouraged to take a cool-down rest in the shade,
  • acclimatization and weather monitoring,
  • high heat procedures,
  • employee and supervisor training:
  • responding to symptoms of possible heat illness,
  • how emergency medical services will be provided should they become necessary,
  • how emergency medical services providers will be contacted,
  • how employees will be transported to a point where they can be reached by an emergency medical service provider if necessary,
  • how, in the event of an emergency, clear and precise directions to the worksite will be provided as needed to the emergency responder, and
  • how a designated person will be available to ensure that emergency procedures are invoked when appropriate.

Employees and supervisors must be trained on these procedures so that they understand and implement the employer's basic approach. The most successful employers make this training a matter of teamwork and profit from a team approach to making the system work.

These procedures must be in writing and made available to employees and to representatives of DOSH upon request. The employer may choose to integrate the procedures into the employer's IIPP.

11a. What is acclimatization, and how should employers address it under the heat-illness prevention standard?

What is acclimatization: Acclimatization is the temporary and gradual physiological change in the body that occurs when the environmentally induced heat load to which the body is accustomed is significantly exceeded. In more common terms, the body needs time to adapt when temperatures rise suddenly, and an employee risks heat illness by not taking it easy when temperatures are hot, or a heat wave strikes, or when starting a new job that exposes the employee to heat to which the employee's body hasn't yet adjusted.  Acclimatization peaks in most people within four to fourteen days of regular work for at least two hours per day in the heat.

Why employers and employees need to understand acclimatization and act appropriately when acclimatization is needed: It is important for employers and employees to understand that inadequate acclimatization can imperil anyone exposed to conditions of heat and physical stress significantly more intense than what they are used to. Employers must understand that they are responsible for the working conditions of their employees, and in addition to monitoring weather reports, they must act effectively when conditions result in sudden exposure to heat their employees are not used to.

Acclimatization is an immediate consideration that should result in direct action by the employer if, due to a sudden heat wave, employees are working at temperatures to which they haven't been exposed for several weeks or longer. New employees are among those most at risk of suffering the consequences of inadequate acclimatization, heat wave or not. An employer with new employees should be extra-vigilant, try to find ways to lessen the intensity of the employees' work during a two-week break-in period, and recognize immediately symptoms of possible heat illness.

Training for employees and supervisors must include the importance of acclimatization, how it is developed, and how the employer's procedures address it. As is true with all training, employers must ensure that their work procedures are consistent with the information provided in training.

11b. What are high heat procedures and what industries are required to comply with this subsection?

The following industries, in addition to the elementary provisions of this standard, are subject to the requirements for High-heat procedures in section (a) (2):

  • Agriculture
  • Construction
  • Landscaping (except for employment by an employer who operates a fixed establishment where the work is to be performed and where drinking water is plumbed)
  • Oil and gas extraction
  • Transportation (except for employment that consists with operating and air-conditioned vehicle and does not include loading and unloading)

When the temperature equals or exceeds 95 degree Fahrenheit, employers listed in the industries noted above, shall implement the high-heat preventive procedures listed in subsection (e):

  • Ensuring that effective communication by voice, observation, or electronic means is maintained so that employees at the work site can contact a supervisor when needed.  An electronic device, such as a cell phone or text messaging device, may be used for this purpose only if reception in the area is reliable.

This preventive measure is particularly important in circumstances where the supervisor is not present at the site and needs to be immediately alerted of a problem, such as when the outdoor temperature has suddenly spiked or the water used for replenishing containers have run out.  

  • Observing employees for alertness and signs or symptoms of heat illness. 

Recognition of signs or symptoms of heat illness by a supervisor is crucial for assuring that sick workers be provided immediate access to shade and medical treatment.  Delay of prompt medical response is likely to occur if employees working individually or in small groups suffer heat syncope, disorientation or loss of consciousness or any other symptoms of heat illness without the supervisor’s knowledge.

In instances where employees work in small groups without a supervisor present throughout the shift, the supervisor may designate an employee with sufficient experience and training to look for signs and symptoms of heat illness. It must also be reiterated that such a designated observer must know what steps to take if heat illness occurs.

  • Reminding employees throughout the shift to drink plenty of water.

The Cal/OSHA Heat Illness Studies revealed that when high temperatures were present, some workers reported that they were more likely to skip drinking water and or taking  rest breaks because they were in a rush to finish their work, and did not realize this could increase their risk of heat illness.

  • Close supervision of a new employee by a supervisor or designee for the first 14 days of the employee’s employment by the employer, unless the employee indicates at the time of hire that he or she has been doing similar outdoor work for at least 10 of the past 30 days for 4 or more hours per day.

These heat illness studies also showed the importance of supervising new employees to ensure that necessary preventive measures such as frequent drinking of water and taking cool down breaks are followed.

12. How is training evaluated for compliance with the standard?

The basic test of training is its effectiveness. The standard lists several items of training information content, and DOSH evaluates compliance with the training requirements by looking at the content as well as the manner in which it has been presented.  In a nutshell,  the test of compliance with the training requirements of this standard is whether the training has occurred, whether the required content has been provided, and whether the training has been effective overall in communicating the essentials to employees.

In addition to effective training, this training must be provided to each supervisory and non-supervisory employee before work that should reasonably be anticipated to result in exposure to the risk of heat illness begins.  Training employees and supervisors about heat illness during colder seasons without follow-up refresher training as the heat season begins may be counter-productive, since essential details will be forgotten over time without reinforcement and actual practice.

An employer should tailor training material obtained from a reputable source so that it applies to the employer's particular work situation and employees. An employer using a "one-size-fits-all" product needs to understand the information provided and to add and subtract whatever is necessary to make it relevant to the employer's individual work situation.

Cal/OSHA has often heard from employers that training must be frequently reinforced to be effective. Some employers use a daily "tailgate meeting" approach, where a brief safety reminder about issues considered particularly relevant to the work to be performed that day is given every day before starting work. In addition, to be effective, employee training must be in a language employees can understand. The Injury and Illness Prevention Program standard requires that an employer have a system for communicating with employees in a form they can readily understand on matters of occupational safety and health, including provisions designed to encourage employees to inform the employer of hazards at the worksite without fear of reprisal.

As part of their evaluation of compliance, Cal/OSHA personnel ask a representative number of supervisory and non-supervisory employees questions about required training elements. They are asked questions to determine whether they received training and whether they can exhibit sufficient understanding of the training content to indicate that the information was conveyed using training methods generally recognized as effective.

The intent of such questions is not to test for answers that are always correct; rather, it is to look for the indicators of effective training that come with a good-faith and sincere effort to get across essential and complete information.

The importance of supervisory training cannot be overstated.  The 2006 Cal/OSHA Heat Illness Case Study showed that 63% of the supervisors of employees who died from heat stroke had not been trained in the prevention of heat illnesses, the opposite from the training-rate statistic for non-fatal illnesses.

In addition to the elements required for employee training, the supervisor’s training must include:

  • Being completely up to speed on the training content provided to the employees,
  • the procedures the supervisor must follow to implement the company’s heat illness prevention plan,
  • the procedures to follow when an employee exhibits symptoms consistent with possible heat illness, including which steps to follow to provide first aid and immediate medical treatment,
  • how to monitor weather reports and how to respond to hot weather advisories.

13. What procedures must an employer have for responding to symptoms of possible heat illness, including how emergency medical services will be provided should they become necessary?

In developing procedures for responding to symptoms of possible heat illness, the employer must first take into account whether a qualified, appropriately trained and equipped person is available to render first aid. If there is no such person, the employer should consider designating an employee to be a first-aid provider and have that employee receive first-aid training and any necessary equipment.

An appropriately trained and equipped first-aid provider who is available at the site can determine the appropriate response when an employee is experiencing possible symptoms of heat illness. This response may range from drinking water and resting in the shade to summoning emergency medical attention.

If no first-aid trained person is available 2 , any situation in which an employee is showing symptoms of possible heat illness should result in calling for emergency medical services. The employer's procedures should also include the taking of immediate steps to keep a stricken employee cool and comfortable once emergency service responders have been called. The goal is to reduce the progression to more serious illness (which can be rapid and include symptoms such as loss of consciousness, seizures and mental confusion).

All employees and supervisors must be trained on every detail of the employer's emergency response procedures.

14. What procedures should an employer have for contacting emergency medical services, and if necessary, for transporting employees to the point where they can be reached by an emergency medical services provider?

The importance of rapidly and effectively obtaining emergency medical services in the event of a serious injury or illness cannot be overstated. Particularly at non-fixed worksites or where there is difficult access, the employer, having evaluated whether the worksite is served by the 911 system, needs to be ready to contact and communicate with emergency responders.

Training must include the information necessary for effective emergency preparedness. This includes the procedures to be used in responding to an employee showing indications of heat illness, contacting emergency medical services, and providing directions to the worksite. Where the employees themselves are not capable of communicating directly with emergency services and giving directions to their location, the employer must ensure that a designated person who can communicate is identified to employees and is immediately available to contact emergency services.

15. What procedures should an employer have to make sure that, in an emergency, clear and precise directions to the worksite can and will be provided to emergency responders, and that a designated person will be available to invoke emergency procedures when appropriate?

Clear and precise directions to the worksite are crucial to ensuring that emergency medical assistance is provided without delay.  Particularly for mobile crews, a map of their location or detailed instructions to the worksite will be necessary to provide precise directions to emergency responders. 

A designated person that has been trained on emergency procedures must also be available to prevent situations that have occurred in the past, where workers or supervisors delayed calling emergency responders, because of lack of clear procedures, or lack of precise location directions, which has resulted in deaths.

16. Where can I get more information on heat illness?

Numerous resources and heat illness publications can be found online at this link:

1. Employees who use chemical protective clothing such as hazmat suits designed to be impervious to chemical liquids and vapors, or other clothing or body coverings that significantly interfere with the body's ability to dissipate heat compared with normal clothing, can be at risk of heat illness even when temperatures are considered mild. Employers with these kinds of employees are required to evaluate the extra heat burden and determine an appropriate temperature trigger for having shade actually present.

2. Employers have a legal obligation under certain conditions to provide onsite, trained first-aid responders.