# Air in gas.

**Citation:** 49 CFR 193.2423  
**Type / status:** regulation / historical  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** 1999-10-01  
**Published:** Not stated

Where incoming gas to liquefaction equipment contains air, each operator shall provide a means of preventing a flammable mixture from occurring under any operating condition.

## Document text

Where incoming gas to liquefaction equipment contains air, each operator shall provide a means of preventing a flammable mixture from occurring under any operating condition.

## Provenance

- Official: Yes
- Source: <https://www.govinfo.gov/app/details/CFR-1999-title49-vol3/CFR-1999-title49-vol3-sec193-2423>
- Source ID: `govinfo-cfr`
- SHA-256: `1fb9938069f7b286e7f8d1d635dcef0c6043b41b5728f7051142f5f80a8d9977`
- Retrieved: 2026-08-12T01:41:23.231Z
- Exported: 2026-08-23T16:13:20.695Z
- Document slug: `49-cfr-193-2423`

### Source metadata

```json
{
  "part": "193",
  "section": "193.2423",
  "subpart": "Subpart E—Equipment",
  "annualEdition": 1999,
  "revisedAsOf": "1999-10-01",
  "govInfoPackage": "CFR-1999-title49-vol3",
  "legalStatus": "official-annual-cfr-edition",
  "effectiveDateNote": null,
  "historicalAnchor": true,
  "historicalAnchorNote": "The section appears in an official annual CFR edition but is absent from the connected current eCFR corpus.",
  "jurisdiction": "US"
}
```