OSHA's 2024 Heat Rule and Cooling Hat Inserts: What Safety Managers Need to Know

TL;DR: OSHA's proposed Heat Injury and Illness Prevention standard, advanced in 2024, requires employers to identify heat hazards, implement written heat injury prevention plans, and provide cooling measures when heat-index thresholds are exceeded. Cooling hat inserts — used inside existing hard hats — are one of the simplest PPE-compatible cooling interventions to add to an existing safety program.

What the 2024 rule actually requires

The proposed rule applies to employers with covered workers exposed to heat indexes of 80°F (initial heat trigger) or 90°F (high heat trigger). Above those thresholds, employers must:

• Identify heat hazards through workplace monitoring
• Develop and implement a written Heat Injury and Illness Prevention Plan (HIIPP)
• Provide access to cool drinking water and paid rest breaks in shaded or air-conditioned areas
• Acclimatize new and returning workers over 7-14 days
• Implement cooling measures — the category that cooling hat inserts fall under
• Monitor workers for signs of heat-related illness

The rule does not mandate any specific cooling technology. It requires that cooling measures be provided — the choice of technology (cooling vests, cooling hats, cooling towels, cooling inserts) is left to the employer.

Why cooling hat inserts fit well in industrial HIIPPs

For any workforce that wears ANSI-rated hard hats — construction, utilities, oil and gas, manufacturing, warehousing — the head is the hardest area to cool. Traditional cooling products create specific problems inside PPE:

• Evaporative cooling towels (e.g., Ergodyne Chill-Its PVA, Frogg Toggs Chilly Pad) are wet by design. Worn inside a hard hat, they saturate the suspension webbing and make crews remove the hat within 30 minutes.
• Cooling caps worn instead of a hard hat void the ANSI certification.
• Full cooling vests cool the torso but do not address the scalp, which is where significant heat loss occurs in active workers.

A phase-change cooling insert — Chiller Body is the original patented example (U.S. Patent No. 11,266,193) — addresses this by fitting inside the existing hard hat. The insert is sealed and dry on the outside, so the hard hat suspension stays clean. The phase-change material activates at 65°F (18°C) and does not transfer moisture to the wearer. It does not affect the ANSI Type I certification of the hard hat itself.

A practical rollout for a 50-worker crew

If you are an EHS manager building a program against the 2024 rule, here is a workable pattern:

1. Issue a 2-pack per worker as part of the summer PPE kit. That gives each worker an active insert plus a rotation insert.
2. Stage coolers on-site — one per crew zone — with ice and spare frozen inserts. 4-6 inserts per worker covers an 8-hour shift.
3. Train swap cadence into the normal rest-break cycle. OSHA-mandated rest breaks at 90°F heat index become the natural swap point.
4. Document it in the HIIPP. The written plan should describe the cooling intervention by type, issue cadence, and rotation protocol.
5. Monitor and adjust. Under the proposed rule, employers must monitor for heat-related illness signs — dizziness, confusion, cessation of sweating. Cooling inserts supplement but do not replace active monitoring.

How cooling hat inserts stack up vs. other cooling PPE

No single cooling technology is "best" for every program. Most mature EHS programs use a layered approach:

• Cooling vests — best for intense, short-duration, stationary work (welders, foundry workers). Expensive per unit.
• Evaporative neck towels and bandanas (Ergodyne Chill-Its, Frogg Toggs Chilly Pad) — best for workers in dry climates with water access. Cheap. Struggle in humid Southeast / Gulf Coast conditions.
• Cooling hat inserts — best for workers who must wear hard hats, for humid conditions, and for rotating shifts where workers move between indoor and outdoor zones. Mid-priced.
• Hydration packs + shade + acclimatization — the baseline required by the rule regardless of cooling PPE.

Cost calculation for a 50-worker site

At $39.95 for a 2-pack (bulk pricing lower for 30+ units), a 50-worker summer rollout with 4 inserts per worker runs roughly $2,000-3,000 — similar to a single cooling vest for a single welder. For seasonal industrial crews this is a small fraction of the overall PPE budget and considerably less than the cost of a single heat-related OSHA citation or workers' compensation claim.

What to ask your supplier

If you are evaluating cooling hat inserts for an EHS program, verify the following:

• ANSI Type I hard hat compatibility — confirmed in writing for the specific hard hat model your crew wears.
• Phase-change activation temperature — 65°F (18°C) is standard; lower temperatures can be uncomfortable for extended use.
• Sealed construction — the insert should be dry on the outside with no moisture transfer to the suspension.
• Reusability — expect hundreds of freeze-thaw cycles from a quality insert.
• Bulk/volume pricing and rollout support — a supplier that does not offer a program plan is not ready to support a crew rollout.

Additional reading

For the category overview — how phase-change cooling differs from evaporative cooling — see our category explainer. For a side-by-side comparison against the most common evaporative products, see our comparisons page, including Chiller Body vs Ergodyne Chill-Its.

For heat-stress program planning, see our Heat Stress Prevention and Safety Managers pages.