# Commonwealth of Kentucky — Pipeline Safety Interpretation

**Citation:** PI-75-015  
**Type / status:** guidance / guidance  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** Not stated  
**Published:** 1975-04-14

PI-75-015 response to Commonwealth of Kentucky concerning 192.625.

## Document text

<<<PAGE 1>>>

April 14, 1975
Mr. Roger Fletcher
Commonwealth of Kentucky
Public Service Commission
Capital Plaza Tower-24th Floor
Frankfort, Kentucky 40601
Dear Mr. Fletcher:
Thank you for your recent letter addressed to Mr. Jim Abbee of this Office, asking:
Would a utility company be considered to have complied with [49 CFR 192.625] if the
natural odor of the gas is detectable at the concentration of one-fifth of the lower
explosive limit?
The purpose of Section 192.625 is to ensure that a concentration of combustible gas in air equal
to one fifth of the lower explosive limit of the mixture is detectable by the sense of smell. To
accomplish this objective, paragraph (a) of Section 192.625 requires that combustible gases be
"odorized" in accordance with that Section.
If, however, a combustible gas is itself a natural odorant and can be smelled at the requisite
concentration of gas in air, the requirement that the gas be odorized would not apply. At the
same time, the other requirements in paragraphs (c)-(f) of Section 192.625, applicable to the
odorant in combustible gases, must be met.
We trust this satisfactorily answers your inquiry.
Sincerely,
Joseph C. Caldwell
Director
Office of Pipeline Safety
dal\192\625\75-04-14
1

## Provenance

- Official: Yes
- Source: <https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1975/PI75015.pdf>
- Source ID: `phmsa`
- SHA-256: `5e3edcad4a468ab0d393c9954d0c1f5c780b7adfc683a38ff2e0a7ceeaf9a54a`
- Retrieved: 2026-08-20T00:59:31.977Z
- Exported: 2026-08-22T23:05:08.051Z
- Document slug: `phmsa-interpretation-pi-75-015`

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