When it comes to heat illness prevention, the regulatory landscape continues to evolve, as seen with the Occupational Health and Safety Administration’s (OSHA) National Emphasis Program (NEP) and the Proposed Heat Injury and Illness Prevention in Outdoor and Indoor Work Settings Rulemaking. Some states have created their own standards. With regulations being implemented and looked into, there’s a growing concern for worker wellbeing when it comes to exposure to heat. In fact, according to the National Weather Service, heat is the top weather-related killer in the U.S.
This article will make sure you’re up to date with the latest in heat stress regulations, whether it’s at the national or state level.
National Heat Safety Directives
There is currently one official heat safety directive that expires this year, OSHA’s National Emphasis Program.
What is it: The National Emphasis Program on Outdoor and Indoor Heat-Related Hazards is designed to protect workers from heat-related hazards, injuries, and illnesses in both indoor and outdoor environments.
Expiration date: April 2026
This NEP creates a framework for targeted inspections and evaluation of workplace safety measures.
Here is what the NEP means for your organization:
- Heat Priority Days: Whenever the local heat index is expected to reach 80°F or higher, a “Heat Priority Day” is triggered. On these days, the agency shifts its focus toward active compliance assistance and inspections in high-risk industries.
- Targeted Industry Inspections: On any day the National Weather Service issues a heat warning or advisory, OSHA conducts pre-planned (programmed) inspections in industries known for high heat exposure, such as construction, agriculture, and manufacturing.
- Mandatory Investigations: Regardless of whether a business is in a “targeted” industry, OSHA will investigate any heat-related fatality, catastrophe, or formal complaint immediately.
- Proactive Outreach: The NEP isn’t just about fines; it includes a heavy focus on compliance assistance. On high-heat days, OSHA field staff are authorized to provide technical help and resources to businesses looking to improve their heat illness prevention plans.
- Focus on Acclimatization: A primary goal of NEP inspections is verifying that employers have functional acclimatization procedures in place for new hires and those returning from extended breaks.
Why you should be prepared:
Despite expiring in April of 2026, the NEP has the potential to be extended, as it has in the past and with the potential of the upcoming rulemaking, it’s best to be prepared.
OSHA’s Proposed Rulemaking
Current status:
Although the informal public hearing has been completed, there have been no updates to the status of the proposed rulemaking since. Despite not having an update, it’s best to be prepared in case the rulemaking does come to fruition this year, and staying ahead will make compliance easy.
What does the Proposed Rulemaking Entail?
The Proposed Heat Safety Standard applies to both indoor and outdoor work settings and applies to all employers with 10 or more employees in several industries under OSHA’s jurisdiction. It also introduces new, specific heat index thresholds at 80° F and 90° F that require necessary actions that employers must take for their employees once hit. A heat safety coordinator must also be appointed within each organization, as well as the development of a Heat Injury and Illness Prevention Plan (HIIP), acclimatization protocols and comprehensive training requirements.
For more detailed information about the proposed rulemaking, read our article or visit the OSHA website.
Why you should be prepared:
Preparation for the formal rulemaking is critical because the Notice of Proposed Rulemaking (NPRM), published in July 2024, has already established the “regulatory floor” for what OSHA considers a safe environment. By the time the final rule is published, OSHA expects employers to have already integrated these core requirements into their standard operations to avoid immediate non-compliance and legal liability.
Existing State-Level Heat Safety Standards
There are several existing heat safety standards established at the state level. Currently, only 8 states have official heat safety requirements.
| State | Year Adopted | Setting | Description |
| California | 2005 (Outdoor) / 2024 (Indoor) | Indoor & Outdoor | California was the first state to implement outdoor standards. In July 2024, it added a permanent indoor standard (Section 3396) triggered when indoor temperatures reach 82°F. |
| Minnesota | 1997 | Indoor | This standard regulates “Workroom Temperatures” in indoor environments based on the type of physical activity (light, moderate, or heavy). |
| Washington | 2008 (Updated 2023) | Outdoor | While Washington has the nation’s first year-round outdoor heat rule, its specific indoor standards are still in the second phase of rulemaking as of 2025. It currently applies to all outdoor work environments. |
| Oregon | 2022 | Indoor & Outdoor | Applies whenever the heat index reaches 80°F in both indoor and outdoor settings. It is considered one of the most protective standards, requiring specific rest break schedules when temperatures exceed 90°F. |
| Colorado | 2022 | Outdoor (Agricultural Only) | This rule applies specifically to agricultural workers. It requires employers to provide shade and water when the temperature reaches 80°F and implement “high-heat” procedures at 95°F. |
| Maryland | 2024 | Indoor & Outdoor | Adopted in September 2024, Maryland’s “Heat Stress Standard” covers both indoor and outdoor workers. It requires employers to monitor heat and provide rest, water, and shade once specific triggers are met. |
| Nevada | 2024 | Indoor & Outdoor | Nevada adopted its final heat regulation (R131-24) in late 2024. It applies broadly to workplaces where heat hazards exist and includes requirements for heat illness prevention plans. |
| New York | 2024 (Effective 2025) | Indoor (Schools) | While not a broad occupational rule, New York passed a law in late 2024 (effective Sept 1, 2025) setting maximum indoor temperatures for all public schools. It mandates action at 82°F and relocation at 88°F. |
State-Level Regulations Underway
Although there are currently only 8 states with regulations, there are a handful of states with new worker protections underway.
Arizona – Task Force Recommendations to be enforced before summer 2026
Georgia – Proposed legislation
Illinois – Proposed legislation
Iowa – Proposed legislation
Massachusetts – Proposed legislation
New Hampshire – Proposed legislation
New Jersey – Proposed legislation
New Mexico – Rulemaking under development
New York – Proposed legislation
Pennsylvania – Proposed legislation
Rhode Island – Proposed legislation
Vermont – Proposed legislation
Virginia – Rulemaking mandated and will go into effect by May 1, 2026.
Visit our Map Page
For an interactive look at current and upcoming regulations, check out our Heat Standards Map, featuring an interactive map created and updated by the National Resources Defense Council (NRDC). You can click on each state to learn more about heat standards or upcoming heat standards.
Ensuring Worker Safety in Hazardous Heat Conditions With or Without Regulations
One way you can empower safety leaders and bolster your current heat safety program is to consider adopting technology, such as physiological monitoring, that can provide insights and alerts in real-time before an incident occurs.
With features like customizable thresholds and real-time alerts, heat stress incidents can become virtually nonexistent. It’s taking heat monitoring a step further by looking at an individual’s physiological response, such as looking at core temperature, heart rate, and exertion levels, to determine their ability to safely continue work.
This gives insight that monitoring ambient temperatures can’t provide, a look into what the worker is experiencing, rather than just a read-out of the current heat index or weather conditions.