# CSA/AM Z21.50 — Which OSHA NRTL is recognized for which test standard: all 21 labs' scopes of recognition, cross-referenced For CSA/AM Z21.50, laboratory is UL LLC; standard title is Vented Decorative Gas Appliances, verified against its source on 2026-08-10. - **Laboratory:** UL LLC _(verified: appears in the quote below)_ - **Standard number:** CSA/AM Z21.50 _(verified: appears in the quote below)_ - **Standard title:** Vented Decorative Gas Appliances _(verified: appears in the quote below)_ ## What the source says > CSA/AM Z21.50 | Vented Decorative Gas Appliances | ## Source - https://www.osha.gov/nationally-recognized-testing-laboratory-program/ul Last verified: 2026-08-10. Review by: 2026-12-08. Part of [Which OSHA NRTL is recognized for which test standard: all 21 labs' scopes of recognition, cross-referenced](https://referencesource.org/nrtl-recognition-scopes/).