History1919United Stateshigh confidence

In 1919, the U.S. Bureau of Mines initiated the first respirator certification program in the United States.

Notes on verification

Confirmed by peer-reviewed history (Spelce et al. 2018), CDC/NIOSH historical documents, and an independent LLNL/OSTI technical report citing Held 1978. Sources share a common historical lineage but no contradicting evidence found.

Sources