Heat is now the most-cited indoor and outdoor environmental hazard in OSHA enforcement. On April 8, 2022, OSHA launched a National Emphasis Program on outdoor and indoor heat-related hazards (CPL 03-00-024), authorizing programmed inspections any day the National Weather Service issues a Heat Advisory or the heat index reaches 80°F. ISN, Avetta, and ISNetworld RAVS reviewers have followed suit — Heat Illness Prevention sections that were boilerplate two years ago now get sent back regularly for rework.
This guide walks through the OSHA NEP, the Cal/OSHA standard at Title 8 §3395 (the most prescriptive in the country), the elements of a written program — water/rest/shade, acclimatization, high-heat procedures, training, and emergency response — and what reviewers expect to see.
Why Heat Suddenly Matters in Prequalification
OSHA had no specific heat standard until the NEP, relying on the General Duty Clause (Section 5(a)(1)) for enforcement. Three things changed:
- The 2021 Advance Notice of Proposed Rulemaking opening a federal heat standard (still in proposed-rule status as of 2024)
- The April 2022 National Emphasis Program directing area offices to conduct programmed heat inspections
- State-plan rules in California (§3395), Washington (WAC 296-62-095), Oregon (OAR 437-002-0156), Nevada, Colorado (agriculture), and Minnesota
The combination of programmed inspections and an ANPRM means owner clients (oil and gas, utilities, refining, EPC) now expect every contractor to carry a written heat illness prevention program — even if the contractor's home state has no specific rule. Reviewers cite the NEP directly.
The OSHA National Emphasis Program — CPL 03-00-024
The NEP (effective April 8, 2022, with a three-year initial duration) does several things:
- Triggers programmed inspections on any day the heat index is forecast to be ≥80°F or NWS issues a Heat Advisory/Excessive Heat Warning
- Targets 70+ industries with elevated heat exposure — construction (NAICS 23), agriculture, warehousing, manufacturing, postal, landscaping
- Directs CSHOs (compliance officers) to evaluate access to cool water, rest breaks, shade, acclimatization protocols, training, and emergency procedures
- Cites under the General Duty Clause when a written program is absent or inadequate
The NEP gives contractors a de facto checklist. Whatever the CSHO will inspect is what the written program must address.
Cal/OSHA §3395 — The Prescriptive Benchmark
California has had a heat illness standard since 2005 and rewrote it in 2015 to its current form. Even contractors that never set foot in California should build to §3395 — it is the model OSHA cited in the proposed federal rule.
The §3395 elements:
- Water — fresh, pure, suitably cool, located as close as practicable to where employees are working. Sufficient to provide at least one quart per employee per hour for the entire shift
- Shade — present when temperature exceeds 80°F. Shade must be open to the air or have ventilation, large enough to accommodate all employees on recovery or rest period without touching, and located as close as practicable
- Preventative cool-down rest — employees may take a cool-down rest in the shade for at least 5 minutes when they feel the need to do so
- High-heat procedures at 95°F for specified industries (construction, agriculture, oil and gas, transportation/delivery, landscaping)
- Acclimatization — close observation of new employees during their first 14 days; close observation of all employees during a heat wave
- Emergency response procedures
- Training for employees and supervisors
- Written program in English and the language understood by the majority of employees
The Written Program — Eight Required Elements
Whether you build to Cal/OSHA, Washington, Oregon, or the federal NEP, your written heat illness prevention program should cover eight elements. Reviewers tick them off one at a time.
1. Provision of Water
State the quart-per-worker-per-hour standard. Identify how water is staged (insulated coolers, hydration stations), how it is replenished during the shift, and the maximum distance from the work face. Cup or bottle source. Cleaning and sanitation. For long-distance pipeline or transmission work, name the rotating water-truck schedule.
2. Access to Shade
Define the trigger temperature (Cal/OSHA: 80°F; the NEP uses 80°F heat index as the inspection trigger). Describe the shade structures — pop-up canopies, EZ-Ups with fans, air-conditioned trailers/break rooms, vehicle cabs with AC running. State that shade must be "open to the air or provided with ventilation or cooling" — a closed, hot truck cab is not shade.
3. High-Heat Procedures (95°F+)
Cal/OSHA §3395(e) defines what kicks in at 95°F:
- Effective communication by voice, observation, or electronic means — buddy system or supervisor monitoring of fewer than 20 employees
- Frequent observation for signs and symptoms (designated observer for 20 or fewer employees)
- Designated worker authorized to call for emergency services
- Reminders to drink water frequently
- Pre-shift meetings to review high-heat procedures, encourage water and rest, remind workers to report symptoms
- For agriculture: 10-minute net rest period every 2 hours at 95°F+
4. Acclimatization — The 14-Day Rule
Acclimatization is where most contractors fail. The body adapts to heat over 7-14 days of progressive exposure. New workers and returning workers (off the job 7+ days, or returning from a cooler region) are at dramatically elevated risk. Cal/OSHA requires:
- Close observation of all new employees for the first 14 days on the job
- Close observation of all employees during a heat wave — defined as 80°F+ and at least 10°F higher than the average high of the preceding 5 days
OSHA's recommended schedule: 20% exposure on day 1, increasing 20% per day until day 5 (Rule of 20%). Document acclimatization in the written program by name. Reviewers look for it specifically.
5. Emergency Response
- Procedure for ensuring effective communication with employees
- Procedure for responding to signs and symptoms — heat rash, cramps, heat exhaustion, heat stroke
- Procedure for contacting emergency medical services and providing clear directions to remote sites (lat/long, mile marker, GPS pin)
- Heat stroke is a medical emergency — immediate cooling (cold water immersion, ice packs to neck/groin/armpits, fans) while waiting for EMS. Do not wait for EMS to begin cooling
6. Training — Workers and Supervisors
Required content:
- Environmental and personal risk factors — temperature, humidity, radiant heat, air movement, workload, PPE, alcohol, medications, prior heat illness
- Employer's heat illness prevention procedures — water, shade, cool-down, acclimatization, high-heat, emergency response
- The importance of frequent water consumption — small amounts, frequently, before thirst
- The importance of acclimatization
- Different types of heat illness, their signs and symptoms
- The importance of immediately reporting symptoms in oneself or a coworker
- The procedure for contacting emergency services
- How to provide clear, precise directions to the worksite
Supervisor training adds: how to implement the program, monitor weather forecasts, recognize symptoms, and respond appropriately including initiating emergency procedures.
7. Written Program
Available at the worksite to employees and to representatives of the agency on request. In English and any language understood by the majority of employees. Names the program administrator.
8. Recordkeeping and Program Review
Training rosters, daily heat index logs (the NWS or NOAA forecast for each project zip code), incident reports, and an annual review with revision date.
Heat Index ≥80°F Trigger Water/Shade 1 qt/hr ≤25 ft Acclimatize 14-Day Rule High-Heat ≥95°F Procedures Emergency Cool + EMSHeat Index vs. WBGT
The NEP uses the NWS heat index — a function of temperature and relative humidity, computed in the shade. Industrial hygiene practice (and ACGIH TLVs) uses Wet Bulb Globe Temperature (WBGT), which adds radiant heat (sun) and air movement. WBGT is more accurate for direct-sun outdoor work and is the metric Cal/OSHA recommends for high-radiant-load environments. State which metric the program uses and how it is measured (Kestrel 5400 or equivalent).
Signs and Symptoms — The Cheat Sheet
| Condition | Symptoms | Response |
|---|---|---|
| Heat rash | Red bumps, prickling skin | Move to cool area, dry skin, change clothes |
| Heat cramps | Muscle spasms in legs/abdomen | Stop work, water with electrolytes, rest in shade |
| Heat exhaustion | Heavy sweating, weakness, headache, nausea, cool clammy skin | Move to shade, loosen clothing, water, cool with wet cloth, monitor |
| Heat stroke | Hot dry or sweaty skin, confusion, slurred speech, loss of consciousness, body temp ≥104°F | Medical emergency. Call 911. Aggressive cooling — cold water immersion preferred. Do not delay |
What Reviewers Flag in RAVS
- No trigger temperature stated, or vague language ("when it is hot")
- Acclimatization not addressed by name (14-day, new/returning)
- High-heat (95°F+) procedures missing or merged into general procedures
- Emergency response does not require immediate cooling for suspected heat stroke
- Training section silent on supervisors
- No daily heat index monitoring procedure
- Written program not available in worker's language
- No annual program review
Heat illness prevention sits next to other environmental and health programs. See our respiratory protection program guide (heat + respirator burden compounds quickly), the HazCom program guide, and the ISNetworld RAVS overview.
The Bottom Line
A heat illness prevention program that survives the NEP and ISN review is built on Cal/OSHA §3395 even outside California. Name the trigger temperature (80°F), the high-heat trigger (95°F), the quart-per-worker-per-hour water standard, the 14-day acclimatization observation period, and the immediate cooling response for suspected heat stroke. Train supervisors to monitor weather and to act before symptoms escalate. Review and re-sign the program annually.
PrequalPilot tracks heat illness training rosters, program revision dates, and integrates with daily JSA workflows so heat exposure is documented every shift it matters. See pricing →