Cal/OSHA Has Approved Its California Indoor Heat Illness Rule: Here’s What It Means for CA Employers

The California Division of Occupational Safety and Health (Cal/OSHA) approved a long-awaited indoor heat-illness standard on June 20, 2024.

Before going live, the Office of Administrative Law (OAL) will have 30 days to approve or deny the standard. Cal/OSHA has requested that it go into effective immediately after OAL approval, so it could very well go live in a month.

The standard, Section 3396, requires employers with indoor workspaces of 87 degrees Fahrenheit and above to reduce the room temperature and offer workers other cool-down options.

For indoor workers who wear poor ventilating protective clothing or work near a heat source, employers will instead have to provide cool-down options when the inside temperature reaches 82 degrees Fahrenheit.

What California Employers Will Need to Prepare

While California has had an outdoor heat illness standard since 2006, indoor workers have been left unprotected. Cal/OSHA has been developing this rule since 2017 but has seen many delays due to fiscal concerns. Seven years later, section 3396 is ready to go into effect pending approval by the Office of Administrative Law (OAL), and employers will need to prepare fast.

While this law was designed for indoor workers doing manual labor like manufacturing, shipping, and construction, you could still be in hot water if your office or kitchen A.C. goes out in extreme heat. Here’s the gist of the requirements:

  1. Cool-Down Options

The standard suggests accommodations to combat indoor heat illness, including cooling the workplace (with air conditioning or fans), allowing ample break time in designated cool-off zones, and free access to cold water. In situations where the employer cannot reduce the temperature or heat index of the indoor workspace, they are required to provide employees with “personal heat protective equipment,” which would likely be a type of cooling vest.

  1. Heat Illness Monitoring, Assessment, and Emergency Plan

Supervisors are required to closely monitor staff when a heat wave is expected. They also need to monitor new employees to ensure they acclimate to the work environment safely and keep a record of temperature conditions when they are expected to be high.

It’s important to note that employers will be responsible for recording the temperature in addition to the heat index of indoor workspaces. *Heat index, also called apparent temperature, is what the temperature feels like to the human body when combined with humidity in the air.

In addition, employers will need to ensure that a quick and effective communication pipeline is ready to report a heat illness emergency. Employers are responsible for promptly facilitating appropriate medical attention for heat-related illnesses in an emergency.

*Heat index has important applications for the human body’s cooling mechanism. Perspiration cools the body only when sweat evaporates into the air. When an area’s humidity is higher, it makes it more difficult for perspiration to evaporate. In other words, 82 degrees Fahrenheit can feel much hotter if your workspace is humid.

  1. Heat Illness Prevention Plan

Employers must also create and maintain a detailed heat illness prevention plan with procedures for the abovementioned requirements. This plan may be included as part of the employer’s Illness & Injury Prevention Program, required by Section 3203, or the (outdoor) Heat Illness Prevention Plan, required by Section 3395. Employers must write this plan in English and the language understood by the majority of the employees.

As described in the proposed rule, here are the requirements for the heat illness prevention plan that employers must create:

“(1) Procedures for the provision of water in accordance with subsection (c).

(2) Procedures for access to cool-down areas in accordance with subsection (d).

(3) Procedures, in accordance with subsection (e), to measure the temperature and heat index, and record whichever is greater; identify and evaluate all other environmental risk factors for heat illness; and implement control measures.

(4) Emergency response procedures in accordance with subsection (f).

(5) Procedures for close observation during acclimatization in accordance with subsection (g).”

*Note: this is a detailed summary of the standard via Cal/OSHA. To further understand this rule and its future implications for your business, read it here with the counsel of your labor law attorney.

  1. Training on Heat Illness Prevention

Heat illness training is also required for employees and supervisors, and it must be administered before they begin work in an environment subject to heat illness risk. Guidelines for training differ between employees and supervisors.

For employees, training must include:

“(A) The environmental and personal risk factors for heat illness, as well as the added burden of heat load on the body caused by exertion, clothing, and personal protective equipment.

(B) The employer’s procedures for complying with the requirements of this section, including, but not limited to, the employer’s responsibility to provide water, cool-down areas, cool-down rests, control measures, and access to first aid as well as the employees’ right to exercise their rights under this section without retaliation.

(C) The importance of frequent consumption of small quantities of water, up to four cups per hour, when the work environment is hot and employees are likely to be sweating more than usual in the performance of their duties.

(D) The concept, importance, and methods of acclimatization and of close observation during acclimatization pursuant to the employer’s procedures under subsection (i)(5).

(E) The different types of heat illness, the common signs and symptoms of heat illness, and appropriate first aid and/or emergency responses to the different types of heat illness, and in addition, that heat illness may progress quickly from mild symptoms OSHSB-98(2/98) Page 11 of 14 STANDARDS PRESENTATION TO CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD TITLE 8, DIVISION 1, CHAPTER 4 and signs to serious and life-threatening illness.

(F) The importance of employees immediately reporting to the employer, directly or through the employee’s supervisor, symptoms or signs of heat illness in themselves, or in co-workers.

(G) The employer’s procedures for responding to signs or symptoms of possible heat illness, including how emergency medical services will be provided should they become necessary.

(H) The employer’s procedures for contacting emergency medical services, and if necessary, for transporting employees to a point where they can be reached by an emergency responder.

(I) The employer’s procedures for ensuring that, in the event of an emergency, clear and precise directions to the worksite can and will be provided as needed to emergency responders. These procedures shall include designating a person to be available to ensure that emergency procedures are invoked when appropriate.”

For supervisors, training must include:

“(A) The information required to be provided by subsection (h)(1).

(B) The procedures the supervisor is to follow to implement the applicable provisions in this section.

(C) The procedures the supervisor is to follow when an employee exhibits signs or reports symptoms consistent with possible heat illness, including emergency response procedures.

(D) Where the work area is affected by outdoor temperatures, how to monitor weather reports and how to respond to hot weather advisories.”

Exceptions to This Rule

This rule will not apply to workplaces that meet either of these conditions:

  1. Workplaces that don’t have workspaces with indoor temperatures measuring 82 degrees Fahrenheit when employees are present.
  2. Remote workplaces that are out of the employer’s control (I.E., home, public coffee shop, library).

Why Did Cal/OSHA Create This Standard?

While California was the first state to pass a heat illness prevention standard in 2006, no similar standard has been released for indoor workers. A standardized plan for preventing these heat illnesses will mean better protection for warehouse and factory workers, especially those who work near a heat source or must wear poorly ventilated clothing.

Heat illness prevention is serious business in a warmer state like California. Southern California clocked the highest temperatures ever last year, putting unprotected workers at risk for heat illness such as heat stroke, heat exhaustion, rhabdomyolysis, heat syncope, and more. “Each year approximately 1,000 California workers submit workers’ compensation claims for heat-related illnesses from occupational heat exposure” reports a regulatory assessment conducted by Rand Education and Labor. A total of seven workers died directly from indoor heat illness between 2010 and 2017.

Heat stroke is the most fatal heat illness. It occurs when the human body’s internal cooling mechanisms can no longer lower its internal temperature. In heat stroke, internal body temperatures can climb to 106 degrees Fahrenheit and higher, causing permanent disability or death if left untreated.

California Payroll Is Your Ally

The Cal/OSHA Store

We understand how crucial workplace safety is for employers and employees. That’s why our Cal/OSHA store features compliance products and resources such as specialized labor law posters, ADA signs, and more to keep your business up-to-date and prepared for new legislation.

Heat Illness Resources

Show your workforce that their health & safety in the workplace matters with the heat exhaustion trainings, posters, guides, and postings from our Cal/OSHA Compliance Store.

For more information, visit the DIR’s page on Cal/OSHA’s proposal for heat illness prevention at