Cal/OSHA Section 3395: Outdoor Heat Illness Prevention

California’s Cal/OSHA outdoor heat illness prevention standard, found at Title 8, Section 3395 of the California Code of Regulations, requires every employer with outdoor workers to supply free drinking water, provide shade once it hits 80°F, allow cool-down rest periods on request, train workers and supervisors, maintain a written prevention plan, and follow extra high-heat procedures when temperatures reach 95°F.¹ It applies statewide, to full-time, seasonal, and temporary outdoor workers alike.

Who Section 3395 Covers

The standard reaches every outdoor place of employment in California. “Outdoor” includes open-air sites and partially covered structures like sheds, tents, and lean-tos that don’t meaningfully reduce the heat risk outside. A packing shed with poor ventilation that traps heat qualifies as outdoor. A building with a roof, enclosed sides, and real climate control generally does not.¹

Five industries face every provision of the standard, including the 95°F high-heat procedures, whenever employees perform any outdoor work:

Agriculture
Construction
Landscaping
Oil and gas extraction
Transportation or delivery of agricultural products, construction materials, or other heavy materials

Temporary workers, seasonal staff, and full-time employees receive identical protection.²

Water

Employers must provide fresh, pure, suitably cool drinking water at no cost. The minimum is one quart per employee per hour across the entire shift. If plumbing or another continuous source isn’t available, enough containers must be filled and staged at the start of the shift to cover the full day.³ The water must sit as close as practicable to where people are actually working, so that drinking doesn’t mean a long walk that discourages hydration.⁴ Federal OSHA guidance recommends keeping drinking water below 60°F for maximum cooling effect.⁵

Making workers buy their own water is a violation. In a 2024 enforcement case against a Van Nuys landscaping company, Cal/OSHA treated that practice as a willful violation of the standard.⁶

Shade at 80°F

Once the outdoor temperature in the work area exceeds 80°F, shaded areas must be available at all times employees are present. The shade must be open to the air or ventilated and cooled, located as close as practicable to the work, and large enough to let every employee currently on a break sit in a normal posture, fully in the shade, without touching each other.⁷

The shade doesn’t have to fit the whole shift at once. It has to fit everyone who’s on a break at that moment, and employers can rotate breaks to make that work. During meal periods, shade must accommodate everyone taking their meal on-site.⁷

At or below 80°F, the employer has a choice: provide shade continuously as above, or provide timely access to shade whenever any employee asks for it.⁸

Cool-Down Rest Periods on Request

Any outdoor worker who feels the need to cool down can take a preventative rest in the shade at any time. The employer cannot demand a reason, and the worker cannot be sent back to work in less than five minutes, plus the time it takes to walk to the shade. A supervisor or designee must check in during the rest and ask whether the employee has heat illness symptoms. If symptoms are present, the rest continues until they fully resolve.⁸

These rests are separate from and in addition to regular meal and rest breaks under California labor law. Discouraging them through pressure, dirty looks, or docked pay violates the standard.

What Changes at 95°F

When the temperature hits 95°F, a second tier of requirements activates. The employer must put all of the following in place:

Effective communication between workers and a supervisor by voice, visual observation, or electronic device. Cell phones count only if reception at the site is reliable.
Active observation for alertness and heat illness symptoms using one of these methods: a supervisor watching 20 or fewer employees, a mandatory buddy system, regular radio or phone check-ins with solo workers, or another equally effective approach.
At least one designated and authorized employee on each worksite who can call emergency medical services, with other employees allowed to call if that person is unavailable.
Supervisor reminders throughout the shift to keep drinking water.
A pre-shift meeting reviewing high-heat procedures, encouraging hydration, and reminding everyone of the right to cool-down rest.

⁹

Extra Rule for Agricultural Workers

Agricultural employers face one more requirement at 95°F: workers must take a minimum ten-minute net cool-down rest period every two hours. “Net” means the ten minutes starts once the worker reaches the shade, not when they leave the work station. These rests can overlap with meal or rest breaks already required under the Industrial Welfare Commission orders, so a standard eight-hour day may not need any extra period beyond what’s already scheduled. If the workday runs past eight hours, another cool-down rest is required at the end of the eighth hour, another at the end of the tenth, and so on.¹⁰

Acclimatization

The body needs time to adjust to working in heat, and the first days are when many heat-related deaths occur. Section 3395 addresses this in two ways:

Any worker newly assigned to a high-heat area must be closely observed by a supervisor or designee for the first 14 days. Heat tolerance typically peaks within four to fourteen days of regular work involving at least two hours per day in the heat.
All employees must be closely observed during any heat wave, defined as a day when the predicted high is at least 80°F and at least 10 degrees higher than the average high over the preceding five days.

¹¹

The heat wave definition catches the first hot days of the season rather than only absolute extremes. A crew that has been working through 70°F weather all month is physiologically unprepared for a jump to 90°F, even though 90°F might not seem alarming on paper.

Written Plan and Training

Before anyone steps outside to work, the employer must have a written Heat Illness Prevention Plan. Cal/OSHA inspectors ask for it first. It must spell out how the employer will meet every requirement of Section 3395, what supervisors and coworkers should do when someone shows symptoms, and how to contact emergency medical services, transport a worker to a reachable location if the site is remote, and provide clear directions so paramedics can find the worksite. The plan must be available to any employee who asks and to Cal/OSHA on request.¹⁰

Every outdoor employee and supervisor must be trained before beginning work. Employee training must cover the symptoms of heat cramps, heat exhaustion, and heat stroke; the importance of drinking water frequently; the right to take cool-down rests without retaliation; the employer’s response procedures; and how emergency services will be contacted. Training must be delivered in a language the employee understands.¹² Supervisor training goes further and must cover the procedures the supervisor is personally responsible for, how to monitor employees for symptoms, and the steps to follow when someone shows signs of heat illness, including when to call for emergency help.

If Your Employer Isn’t Complying

California Labor Code Section 6310 prohibits firing, demoting, suspending, or otherwise punishing any employee for exercising their safety rights. That protection covers taking a cool-down rest, reporting a heat violation, refusing to work in conditions that violate the standard, and filing a Cal/OSHA complaint. An employer who retaliates is liable for reinstatement, lost wages, and lost benefits, and a willful refusal to rehire or restore an employee found eligible for reinstatement is a misdemeanor.¹³

To report a heat safety violation, call the nearest Cal/OSHA Enforcement District Office between 8 a.m. and 5 p.m. on weekdays. By law, the name of a complainant is kept confidential unless the person requests otherwise.¹⁴

Penalties

For citations issued on or after January 1, 2025:

Serious violations: up to $25,000 per violation
Willful or repeat violations: up to $162,851 per violation, with a minimum of $11,632 for willful violations
General and regulatory violations, including posting and recordkeeping: up to $16,285 per violation

¹⁵

A single inspection can produce multiple violations. An employer with no written plan, no shade, no water, and untrained supervisors could face four or more separate citations from one visit. The 2024 Parkwood Landscape case reached $276,425 because Cal/OSHA classified the violations as willful, meaning the employer knew the requirements and deliberately ignored them. That was the agency’s first willful heat citation in more than five years.⁶

Indoor Work Is Covered by a Separate Rule

Section 3395 applies only to outdoor work. Since July 23, 2024, California has had a separate indoor heat illness prevention standard at Title 8, Section 3396, which starts applying when the indoor temperature exceeds 82°F and requires measurement and recording of temperature or heat index once it reaches 87°F. Indoor employers must provide at least one cool-down area kept below 82°F and implement feasible engineering controls like ventilation before relying on administrative measures. The indoor standard does not include the 95°F high-heat procedures found in Section 3395.¹⁶

1
Department of Industrial Relations. California Code of Regulations Title 8 Section 3395 Heat Illness Prevention in Outdoor Places of Employment
2
Department of Industrial Relations. California Code of Regulations Title 8 Section 3395 Heat Illness Prevention in Outdoor Places of Employment – Section: (a) Scope and Application
3
Department of Industrial Relations. California Code of Regulations Title 8 Section 3395 Heat Illness Prevention in Outdoor Places of Employment – Section: (c) Provision of Water
4
California Department of Industrial Relations. Cal/OSHA – Sufficient Amounts of Drinking Water
5
Occupational Safety and Health Administration. Keeping Workers Well-Hydrated
6
Department of Industrial Relations. Cal/OSHA Issues $276,425 Citation for Willful-Serious Heat Violations
7
California Department of Industrial Relations. Heat Illness Prevention – Shade and Other Cooling Measures
8
Department of Industrial Relations. California Code of Regulations Title 8 Section 3395 Heat Illness Prevention in Outdoor Places of Employment – Section: (d) Access to Shade
9
California Department of Industrial Relations. Heat Illness Prevention – High Heat Procedures
10
Department of Industrial Relations. California Code of Regulations Title 8 Section 3395 Heat Illness Prevention in Outdoor Places of Employment – Section: (e) High-Heat Procedures
11
Department of Industrial Relations. California Code of Regulations Title 8 Section 3395 Heat Illness Prevention in Outdoor Places of Employment – Section: (g) Acclimatization
12
Department of Industrial Relations. California Code of Regulations Title 8 Section 3395 Heat Illness Prevention in Outdoor Places of Employment – Section: (h) Training
13
California Legislative Information. California Labor Code Section 6310
14
Department of Industrial Relations. How to File a Complaint with Cal/OSHA
15
Department of Industrial Relations. Cal/OSHA Increases Civil Penalty Amounts for 2025
16
Department of Industrial Relations. Cal/OSHA Heat Illness Prevention Guidance and Resources