Cal/OSHA Heat Illness Training Guide

Training Is Not Optional, and General Orientation Is Not Enough

California employers are required to provide heat illness prevention training before employees and supervisors begin working in conditions that create a risk of heat illness. That requirement applies under both Section 3395 (outdoor) and Section 3396 (indoor), and it applies regardless of how long an employee has worked for the company or how much experience they have.

What many employers do not realize is that the content requirements for supervisor training are meaningfully different from those for worker training. A single, unified training session that covers the same material for everyone does not satisfy Cal/OSHA’s requirements. Supervisors have specific obligations under both heat illness prevention standards, and they must be trained to fulfill those obligations before they are placed in a supervisory role during heat conditions.

This article breaks down what the training must cover for each group, how it must be documented, and where most employers find gaps when their programs are reviewed.

Training Requirements for All Employees

Both Section 3395 and Section 3396 require that all employees receive training that addresses the following topics:

The environmental and personal risk factors for heat illness. Employees must understand what conditions increase the risk of heat illness, including high temperatures, high humidity, direct sun exposure, heavy workloads, and individual factors such as age, medical conditions, and acclimatization status.
The employer’s procedures for complying with heat illness prevention requirements. General awareness of heat safety is not sufficient. Training must address the specific procedures in place at the employer’s workplace, including where water is located, how to access shade or cool-down areas, and how cool-down rest periods are managed.
The importance of drinking water frequently. Employees must understand that waiting until they feel thirsty is a sign that dehydration has already begun. Training must reinforce frequent, proactive hydration.
The importance of acclimatization. New employees and those returning from absence must understand why gradual heat exposure is required and what the acclimatization schedule looks like for their work environment.
The signs and symptoms of heat illness. Employees must be able to recognize the early and advanced signs of heat illness in themselves and in their coworkers, including heat cramps, heat exhaustion, and heat stroke.
The importance of immediately reporting signs of heat illness. Employees must know who to report to, how to report, and that they will not face retaliation for taking a cool-down rest or reporting a coworker’s symptoms.

How to contact emergency services. Employees must know how to summon emergency response, what information to provide, and how to communicate their location in the field or facility.

Additional Training Requirements for Supervisors

In addition to all of the content required for worker training, supervisors must receive training that covers a distinct set of responsibilities that correspond to their role in implementing the heat illness prevention program.

How to implement the employer’s heat illness prevention procedures. Supervisors must understand their specific obligations, including scheduling cool-down rest periods, ensuring access to water and shade or cool-down areas, and monitoring acclimatization for new or returning employees.
How to monitor weather reports and respond to heat advisories. Under the outdoor standard, supervisors are expected to check temperature and heat index forecasts before shifts and adjust work assignments or rest schedules when high-heat conditions are anticipated.
How to respond when an employee shows signs of heat illness. Supervisors must know how to assess symptoms, when to provide first aid, when to call emergency services, and how to document what occurred.
High-heat procedures. For outdoor work, supervisors must understand the specific requirements that activate at 95 degrees Fahrenheit, including mandatory cool-down periods, observation protocols, and pre-shift communication requirements.

Emergency response procedures specific to the worksite. Supervisors must know the emergency contacts for the specific location, how to communicate with workers in remote or isolated areas, and how to coordinate with emergency services if needed.

Indoor vs. Outdoor Training: What Changes

The core content of heat illness prevention training is consistent across both standards, but the application differs depending on the work environment.

For outdoor environments, training must address:

Acclimatization schedules for new and returning employees
High-heat procedures that activate at 95 degrees Fahrenheit
Emergency communication for remote or isolated work areas
Shade requirements and the procedures for accessing shade

For indoor environments under Section 3396, training must additionally address:

The temperature thresholds that trigger requirements (82 degrees and 87 degrees Fahrenheit)
The location and procedures for using the designated cool-down area
How temperature monitoring is conducted in the facility
Enhanced requirements that apply when employees are wearing PPE that traps heat

For employers with both indoor and outdoor operations, training must address both sets of conditions.

When Training Must Occur

Both standards require training to be provided before employees are placed in heat conditions. That means training cannot wait until the first hot day of the season. For existing employees, training should be completed before outdoor or indoor heat conditions are likely to occur. For new employees, training must be completed before they begin working in a heat-exposed environment.

There is no requirement under either standard to repeat training on a fixed annual schedule, but employers are expected to retrain employees when procedures change, when an incident or near-miss suggests that previous training was insufficient, or when a new heat-related risk is identified in the workplace.

Documentation Requirements

Training documentation is one of the most important and most commonly missing elements of heat illness prevention compliance. Cal/OSHA inspectors will ask to see training records during an inspection, and the absence of documentation is treated as evidence that training did not occur.

At minimum, training records should include:

The date the training was conducted
The names of the employees who attended
The topics covered
The name of the person who delivered the training
A signature or acknowledgment from each employee confirming they received the training

Common Training Deficiencies Found During Inspections

Supervisor and worker training treated as identical. One training session for all employees fails to meet the supervisor-specific content requirements.
Training completed after the heat season begins. If training is scheduled as a reaction to the first heat advisory rather than in advance of heat conditions, the employer is already out of compliance.
Training that covers general heat safety but not site-specific procedures. Employees must be trained on the employer’s actual procedures, not general heat awareness content.
No documentation, or documentation that does not reflect content. A sign-in sheet confirms attendance but does not confirm that the required topics were covered.
New employees not trained before their first heat exposure. This is especially common in industries with high turnover, where onboarding and safety training are not tightly integrated.

How PCS Safety Supports Heat Illness Prevention Training

PCS Safety provides OSHA compliance training and consulting services for California employers, including heat illness prevention training designed to meet the content requirements of both Section 3395 and Section 3396. Training can be delivered on-site, via live webinar, or online, and is tailored to the specific work environment and industry of each client.

If you are unsure whether your current training program meets Cal/OSHA’s requirements for both supervisors and workers, a safety program audit and gap analysis can identify what is missing and what needs to be updated before the summer heat season peaks.

Cal/OSHA Heat Illness Prevention Training Requirements: What Supervisors and Workers Must Know