Proposed US federal heat rule for outdoor and indoor work settings (29 CFR 1910.148 NPRM). Not final. Public comment closed Jan 14, 2025; the Trump administration regulatory freeze (Jan 20, 2025) paused rulemaking indefinitely. Rule remains on OSHA's unified agenda without a target finalization date (as of 2026-06). OSHA's National Emphasis Program (NEP, updated Apr 2026) is the current federal heat enforcement vehicle.
Open OSHA Federal Heat Rule NPRM (Proposed) in the interactive Guidance Wiki →
No standalone formula is published for this standard; see programmable logic and parameters below.
Governing metric: Heat index or WBGT
Programmable logic: Initial trigger at 80°F heat index or NIOSH RAL; high trigger at 90°F heat index or NIOSH REL.
This standard does not take WBGT as a required input, and publishes no standalone numeric parameter table here; see the governing metric and programmable logic above, and the primary source below.
Required inputs: none
Optional inputs: heatIndexF, wbgtC, metabolicRateW, acclimatization, workerStatus