Reference

WBGT and the heat index are different quantities: one is a four-factor instrument reading occupational limits are written against, the other a shade-at-rest screen from temperature and humidity. This guide covers what each measures, the NIOSH workload limits, clothing adjustment factors, and when a phone weather reading fails a jobsite.

Federal OSHA heat enforcement runs on the General Duty Clause and the National Emphasis Program revised April 10, 2026 - the proposed heat standard is not yet law. This guide separates what is enforceable now from what is merely proposed, decodes the 2026 NEP inspection triggers, and lists the program elements employers should run today.