Ahead of summer 2025, in a May 16 announcement, the California Division of Occupational Safety and Health (Cal/OSHA) reminded the state’s employers of its indoor and outdoor heat illness prevention standards.
The agency also reminded employers of educational materials, guidance, model programs, and other resources available from the agency, which offers annual training held statewide in both English and Spanish.
California has separate heat illness prevention program standards for indoor and outdoor workplaces, and Cal/OSHA has compiled a Comparison Chart of Indoor and Outdoor Heat Illness Prevention Standards.
“California workers, especially those laboring outdoors or in hot indoor environments, face serious risks from heat exhaustion, dehydration and other serious conditions, during high temperatures,” Cal/OSHA Chief Debra Lee said in an agency statement. “Our goal is to make sure employers and workers are prepared, informed, and equipped to prevent heat illness before it happens.”
Cal/OSHA also announced the launch of a “first-of-its-kind” Agricultural Enforcement Task Force and Outreach Unit, designed to strengthen enforcement, increase on-site inspections, and expand resources to better reach and protect workers.
California’s rules require that employers have written heat illness prevention plans that include emergency response procedures. Employers must also provide drinking water and proper shade when temperatures exceed 80 degrees Fahrenheit and encourage workers to take a cooldown rest in the shade for at least 5 minutes.
Employers also must train their workers and supervisors.
First summer for Maryland heat rule
The Maryland Occupational Safety and Health Administration (MOSH) published a heat stress standard on September 20, 2024, that became effective September 30. 2025 will be the first summer under Maryland’s new rule.
The Maryland standard contains requirements for a heat stress prevention and management program, heat acclimatization, shade, drinking water, procedures for managing high-heat working conditions, emergency response, and training. Maryland also requires employers in the state to monitor the heat index.
The Maryland standards apply to both indoor and outdoor work environments. Acclimatization requirements involve gradually increasing heat exposure times over a 5- to 14-day period, with a maximum 20 percent increase in exposure time each day. Both new employees and those returning from a work absence must undergo a period of acclimatization.
The state agency posted a recording of a webinar explaining the rule on YouTube. MOSH also has a series of employer guides to aid in compliance, including the following:
- Key Requirements: Maryland Heat Stress Standards
- Summary of Key Maryland Requirements fact sheet
- OPTIONAL Heat Illness Prevention (HIP) Model Program for Maryland Employers
Oregon and Washington also have heat illness prevention program standards, and Minnesota has rules for both cold and hot working environments.
There’s no federal heat stress or heat illness prevention standard, but OSHA proposed a heat injury and illness prevention standard last summer that contained planned requirements for water, shade, paid breaks, heat acclimatization, and training.
President Donald Trump signed an Executive Order on January 31 directing federal agencies to repeal 10 regulations or guidance documents for each new rule or guidance established. He signed an order on February 19 directing agencies to compile lists of regulations for removal.