# Ex m / ma / mb / mc — Certification marks and hazardous-area classifications: cross-market equivalences For Ex m / ma / mb / mc, governing standard / law is EN/IEC 60079-18, verified against its source on 2026-08-11. - **Designation:** Ex m / ma / mb / mc _(verified: appears in the quote below)_ - **Governing standard / law:** EN/IEC 60079-18 _(verified: appears in the quote below)_ ## What the source says > Encapsula on - Ex m / ma / mb / mc EN/IEC 60079-18 ## Source - https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf 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/).