As summer heat waves continue across California, Cal/OSHA is reminding employers in outdoor industries to comply with the state's Heat Illness Prevention Standard. The agency has issued a series of advisories throughout the year — most recently in March and June 2026 — urging employers to review their safety protocols ahead of forecasted heat waves, particularly in Southern California counties under National Weather Service heat advisories.
These are part of Cal/OSHA's ongoing Heat Illness Prevention special emphasis program, which combines enforcement of the heat standards with multilingual outreach and training for employers and workers. The agency has a history of conducting unannounced inspections during active heat waves — it did so as recently as 2022 across construction, agriculture, tree-trimming, landscaping, car wash, and warehouse worksites — and it continues to treat high-heat conditions as an enforcement priority in industries with elevated outdoor exposure.
What the standard requires
California's Heat Illness Prevention Standard (Title 8, Section 3395) applies to outdoor worksites statewide. It requires employers to provide:
- Clean drinking water, available at all times
- Access to shade whenever temperatures reach or exceed 80°F
- Additional high-heat procedures — including regular observation of workers for signs of heat illness and established methods of effective communication — once temperatures reach or exceed 95°F, in industries with specific high-heat requirements: agriculture, construction, landscaping, oil and gas extraction, and the transportation of agricultural products, construction materials, or other heavy materials
- A written Heat Illness Prevention Plan, with training for supervisors and employees on recognizing symptoms and responding to emergencies
Why construction and similar outdoor trades are at elevated risk
Outdoor construction trades — including excavation, concrete, and specialty trades like fencing — often work without permanent shade structures, across shifting job sites, and with physically demanding tasks (digging, mixing concrete, operating machinery) that increase heat strain. National data has also shown construction workers bear a disproportionate share of occupational heat fatalities relative to their share of the workforce, and some trades — such as cement masons and roofers — carry especially high heat-related fatality risk. That underlying risk is why these sectors are consistently named in Cal/OSHA's advisories and in federal OSHA's own heat-hazard emphasis program, not because of any special campaign targeting a particular trade.
Penalties and enforcement
Cal/OSHA classifies failures to provide required water, shade, or high-heat monitoring as serious violations, which carry substantial civil penalties, with escalating fines for repeat or willful violations. Inspectors also have authority to halt operations at a site where conditions present an imminent hazard.
What to do now
With Cal/OSHA advisories emphasizing that even early-season heat waves can catch unacclimatized workers off guard, safety compliance professionals recommend that outdoor contractors:
- Track daily temperatures and heat advisories for each job site
- Hold morning tailgate safety briefings before high-heat days
- Stock mobile shade and water stations, especially for crews that move between short-term job sites
- Pay particular attention to newer or returning workers who haven't yet acclimatized to the heat