OSHA's Heat NEP Is Back — And It Has Teeth: What Employers Must Know for 2026

Effective April 10, 2026 | Directive CPL 03-00-024

OSHA's National Emphasis Program (NEP) on heat-related hazards was fully revised and relaunched on April 10, 2026, replacing the original 2022 directive for a new five-year enforcement term. This isn't a paperwork update - it expands which industries are targeted, raises documentation expectations for inspectors, and creates new pathways for unannounced site visits.

If you operate in any environment where workers are exposed to heat, indoors or outdoors, here is what changed and what you need to have in place before summer.

What Is OSHA's National Emphasis Program?

A National Emphasis Program is a formal OSHA directive that shifts the agency from reactive enforcement (waiting for complaints) to proactive, unannounced inspections of targeted industries - no prior incident required.

The Heat NEP first launched in April 2022. After a one-year extension in January 2025, it was fully overhauled and relaunched on April 10, 2026, under Directive CPL 03-00-024. It will remain active for up to five years.

What Triggers an OSHA Heat Inspection?

This is the part most employers don't know - and it matters enormously.

Heat advisory days. Whenever the National Weather Service issues a heat warning or advisory for your area, OSHA Area Offices are authorized to begin unannounced, programmed inspections of targeted businesses. No complaint needed.

Heat priority days (80°F+ heat index). If an inspector is already on your site for any reason and the heat index is 80°F or higher, they are required to assess heat hazards and can expand the scope of the visit on the spot.

Drive-by observations. Inspectors traveling between sites on advisory days are explicitly instructed to stop at outdoor worksites they observe - construction crews, roofing operations, road workers. These are logged as "Unprogrammed Emphasis Hazard" inspections, a new category added in 2026.

Complaints and incidents. Any employee complaint about a lack of water, rest, or shade is prioritized for an on-site visit. So is any employer-reported heat hospitalization or fatality.

What Changed in the 2026 Update?

Expanded Industry Coverage - 55 Industries Now Targeted

The 2026 directive targets 55 high-risk industries, with 22 new sectors added and 46 removed from the original list. Newly added industries include:

• General freight trucking and logistics
• Plastic product manufacturing
• Animal slaughtering and processing
• Scheduled air transportation
• Department stores
• Community food and housing services
• Individual and family services
• Telecommunications carriers

The point OSHA is making: heat is not just an outdoor hazard. Indoor environments with radiant heat sources - industrial kitchens, manufacturing floors, bakeries, warehouses - are explicitly covered.

New Inspector Checklists: Appendix I and Appendix J

The 2026 update added two appendices that directly shape what happens during an inspection.

Appendix I is an 11-point checklist inspectors use to evaluate your heat illness prevention program. It covers:

• Cool water accessibility (NIOSH recommends a cup every 15 minutes)
• Scheduled rest breaks and access to shade or cool rest areas
• Acclimatization protocols for new and returning employees
• Training for workers and supervisors on heat illness recognition and response
• Whether heat monitoring is in place and how it's documented

Appendix J is the citation guidance. It tells inspectors exactly what environmental data they must document - and it significantly raises the bar:

• Heat index
• Dry bulb temperature
• Relative humidity
• Wind speed
• Cloud cover (none, 25%, 50%, 75%, 100%)
• Wet Bulb Globe Temperature (WBGT) - specifically noted as a more accurate indicator of heat effects on the body than dry bulb temperature alone
• Radiant heat sources present at the worksite
• National Weather Service advisories issued on the day of inspection and prior days

Critically: if your site doesn't have its own monitoring records, inspectors are instructed to reconstruct conditions from national weather data sources - which may come from a station miles away. Your best defense is your own site-specific documentation.

Shift to Data-Driven Enforcement

The 2026 update eliminates fixed inspection quotas and removes outdated background criteria. Inspections are now prioritized based on current injury and illness data, industry-specific risk trends, and real-world enforcement history. This makes the program more targeted - and harder to predict.

Why WBGT Is the Right Measurement Standard

OSHA does not mandate a specific measurement method, but Appendix J explicitly identifies WBGT as the more accurate indicator of heat effects on individuals. Here's why it matters.

Heat Index combines temperature and humidity. It's widely available and useful for general awareness.

Wet Bulb Globe Temperature (WBGT) accounts for temperature, humidity, solar radiation, and air movement - everything that determines how heat actually affects the human body during physical work. It's the measurement standard used by the U.S. military, ACGIH (the authoritative occupational health body for heat exposure limits), NCAA athletics, and industrial hygienists worldwide.

For workers doing physically demanding tasks in varied conditions - sun to shade, indoor to outdoor, still air to open sites - heat index alone doesn't give you enough to make defensible decisions. WBGT does.

The Monitoring Problem Employers Get Wrong

The most common mistake: relying on weather apps, forecasts, or airport weather stations to assess worker exposure.

These sources can be miles from your site. They don't capture:

• Radiant heat from asphalt, roofing, or equipment surfaces
• Microclimates across large facilities or job sites
• Limited airflow in semi-enclosed or indoor spaces
• Conditions changing between morning and mid-afternoon

Onsite measurement, at worker height, in actual work areas, is the only way to know what workers are actually experiencing - and the only way to build a defensible record if OSHA reconstructs conditions from a prior day.

How to Build a Compliant Heat Monitoring Program

Step 1: Measure Where Workers Are

Use WBGT monitoring at the location workers are actually performing tasks - not at a central station, not from your phone. For sites where workers move between sun and shade, indoors and outdoors, that means taking readings at each relevant area.

Step 2: Monitor in Real Time Throughout the Day

A safe morning can become dangerous by early afternoon. Heat conditions are dynamic. Take frequent readings during peak heat hours and track trends, not just single readings.

Step 3: Translate Data Into Action

WBGT thresholds from ACGIH and military standards provide clear frameworks for adjusting work/rest cycles, hydration breaks, and work schedules based on measured conditions and workload level. Monitoring without action doesn't protect workers or employers.

Step 4: Document Everything

With OSHA now explicitly reconstructing historical conditions when investigating incidents, your documentation is your defense. Keep records of:

• Environmental conditions (temperature, humidity, WBGT readings)
• Monitoring frequency and times
• Actions taken in response to threshold crossings
• Training records, acclimatization logs, water and rest break documentation

How the Kestrel 5400 Heat Stress Tracker Supports Compliance

For employers in construction, agriculture, trucking, manufacturing, and other industries where workers move across jobsites, a portable, accurate WBGT meter is the practical solution.

The Kestrel 5400 Heat Stress Tracker measures WBGT, heat index, temperature, humidity, wind speed, and wet bulb temperature directly at the location where work is happening. It's the tool of choice for occupational health professionals, the U.S. military, and safety managers who need accurate, field-ready heat data.

For OSHA compliance specifically, the Kestrel 5400 enables you to:

• Take onsite WBGT readings tied to specific tasks and locations with built-in ACGIH and Military Guidelines.
• Monitor conditions throughout the day during peak heat hours and set custom alerts.
• Generate data you can document and present if an inspector reconstructs conditions from a prior day
• Make work/rest and acclimatization decisions based on recognized standards (ACGIH, military)

Frequently Asked Questions

Is WBGT required by OSHA? OSHA does not mandate a specific measurement method. However, OSHA's own 2026 directive (Appendix J) explicitly identifies WBGT as the more accurate measure of heat effects on individuals, and inspectors are expected to document WBGT readings where available. Employers who use WBGT are better aligned with how enforcement is structured.

Can I use a weather app instead of onsite measurement? A weather app tells you conditions at the nearest reporting station - which may be miles from your site and unable to capture radiant heat, microclimates, or limited airflow. OSHA inspectors are instructed to use national weather data to reconstruct conditions when employers don't have their own records. Your site-specific data is the stronger record.

How often should heat stress be monitored? Continuously throughout the day, with increased frequency during peak heat hours. Heat conditions change significantly from morning to afternoon and vary across locations on the same site.

Which industries are now covered by the 2026 Heat NEP? 55 industries total - including construction, agriculture, warehousing, manufacturing, food processing, trucking, telecommunications, and several service sectors. If your workers perform physically demanding tasks in warm environments, indoors or outdoors, treat yourself as in scope. You can review the full list in OSHA’s official directive PDF.

What happens if I don't have heat monitoring records during an inspection? Inspectors are instructed to reconstruct conditions using nationally available weather data. That data may come from a station far from your site and may not reflect actual conditions. Without your own records, you have no way to challenge or contextualize the inspector's findings.

The Bottom Line

OSHA's 2026 Heat NEP creates a direct connection between measured environmental conditions and enforcement. The employers best positioned for inspection are the ones who are already monitoring, documenting, and acting on real data from their own worksites.

For organizations where workers move, and conditions vary - which is most of the 55 industries now targeted - that starts with a portable, accurate WBGT instrument in the hands of a safety manager.

[Learn more about the Kestrel 5400 Heat Stress Tracker →]