# Zone 1 — Certification marks and hazardous-area classifications: cross-market equivalences For Zone 1, market / system is IEC / ATEX; meaning is Explosive atmosphere likely during normal operation, recorded from its source on 2026-08-11. - **Designation:** Zone 1 _(verified: appears in the quote below)_ - **Market / system:** IEC / ATEX - **Meaning:** Explosive atmosphere likely during normal operation _(verified: appears in the quote below)_ ## What the source says > Zone 1 | Explosive atmosphere likely during normal operation ## Source - https://www.inframena.com/hazardous-area-classification-equivalency-guide/ Last verified: 2026-08-11. Review by: 2027-08-11. Part of [Certification marks and hazardous-area classifications: cross-market equivalences](https://referencesource.org/certification-standards-equivalence/).