# GILL RANCH STORAGE LLC — Warning Letter

**Citation:** CPF 12021056WL  
**Type / status:** enforcement / historical  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** Not stated  
**Published:** 2021-08-24

CLOSED warning letter citing 192.12(b)(2).

## Document text

Warning Letter involving GILL RANCH STORAGE LLC. PHMSA's enforcement data identifies the cited regulation as 192.12(b)(2). The case was opened on 2021-08-24 and is reported as closed as of 2021-08-24. Open the official case record for notices, responses, orders, and the latest status.

Official case documents:

12021056WL_Warning Letter_08242021_(20-197118).pdf: https://primis.phmsa.dot.gov/enforcement-documents/12021056WL/12021056WL_Warning%20Letter_08242021_(20-197118).pdf

12021056WL_Warning Letter_08242021_(20-197118)_text.pdf: https://primis.phmsa.dot.gov/enforcement-documents/12021056WL/12021056WL_Warning%20Letter_08242021_(20-197118)_text.pdf

12021056WL_Warning Letter_08242021_(20-197118)_text.pdf

WARNING LETTER
OVERNIGHT EXPRESS DELIVERY
August 24, 2021
Mr. Mark Stauss
President
Gill Ranch Storage LLC
10000 Memorial Drive, Suite 330
Houston, TX 77024
CPF 1-2021-056-WL
Dear Mr. Stauss:
From August 18 to August 20, 2020, California Geologic Energy Management Division
(CalGEM) acting as an agent for the Pipeline and Hazardous Materials Safety Administration
(PHMSA) pursuant to Chapter 601 of 49 United States Code (U.S.C.) inspected Gill Ranch Gas
Storage LLC’s (Gill Ranch) Underground Natural Gas Storage (UNGS) operations located near
Mendota, California.
As a result of the inspection, it is alleged that you have committed a probable violation of the
Pipeline Safety Regulations, Title 49, Code of Federal Regulations (CFR). The item inspected and
the probable violation is:
1. § 192.12 Underground natural gas storage facilities.
(a) …
(b) Depleted hydrocarbon and aquifer reservoir UNGSFs.
(1) …
(2) Each UNGSF that uses a depleted hydrocarbon reservoir or an
aquifer reservoir for natural gas storage and was constructed on or
before July 18, 2017, must meet the provisions of API RP 1171
(incorporated by reference, see § 192.7), sections 8, 9, 10, and 11, and
paragraph (c) of this section, by January 18, 2018, and must meet all
provisions of paragraph (d) of this section by March 13, 2021.



CPF 1-2021-056-WL
Gill Ranch failed to meet the provisions of API RP 1171, Section 8. Specifically, Gill Ranch failed
to include risk related to the storage operation using available information from its bi-annual land
surface elevation monitoring program in accordance with API RP 1171, Section 8.3.2 Data
Sources (Section 8.3.2).
Section 8.3.2 states:
The operator shall use available information such as performance data collected through the
field history, operations and maintenance (O&M) activities, geotechnical data such as well
logs, engineering data, and completion reports to determine susceptibility to threat and
hazard-related events and to assess threat and hazard interaction.
During the inspection, CalGEM inspectors reviewed Gill Ranch’s Risk Management Plan (RMP),
dated July 27, 2020. The inspectors noted that Gill Ranch’s biannual land surface elevation
monitoring program and its basic storage well design indicated understanding of threats posed by
seasonal vertical fluctuation and longer-term subsidence of the ground surface to well and reservoir
integrity. However, Gill Ranch maintained that the program was mandatory, yet, did not include
it as a mandatory component of their RMP.
Therefore, Gill Ranch failed to meet the provisions of API RP 1171, Section 8 as required by
§ 192.12(b)(2).
Under 49 U.S.C. § 60122 and 49 CFR § 190.223, you are subject to a civil penalty not to exceed
$225,134 per violation per day the violation persists, up to a maximum of $2,251,334 for a related
series of violations. For violation occurring on or after January 11, 2021 and before May 3, 2021,
the maximum penalty may not exceed $222,504 per violation per day the violation persists, up to
a maximum of $2,225,034 for a related series of violations. For violation occurring on or after
July 31, 2019 and before January 11, 2021, the maximum penalty may not exceed $218,647 per
violation per day the violation persists, up to a maximum of $2,186,465 for a related series of
violations. For violation occurring on or after November 27, 2018 and before July 31, 2019, the
maximum penalty may not exceed $213,268 per violation per day, with a maximum penalty not to
exceed $2,132,679. For violation occurring on or after November 2, 2015 and before November
27, 2018, the maximum penalty may not exceed $209,002 per violation per day, with a maximum
penalty not to exceed $2,090,022.
We have reviewed the circumstances and supporting documents involved in this case, and have
decided not to conduct additional enforcement action or penalty assessment proceedings at this
time. We advise you to correct the item identified in this letter. Failure to do so will result in Gill
Ranch Gas Storage LLC being subject to additional enforcement action.
No reply to this letter is required. If you choose to reply, in your correspondence please refer to
CPF 1-2021-056-WL. Be advised that all material you submit in response to this enforcement
action is subject to being made publicly available. If you believe that any portion of your
responsive material qualifies for confidential treatment under 5 U.S.C. 552(b), along with the
complete original document you must provide a second copy of the document with the portions
12021056WL_Warning Letter_08242021_(20-197118)_text Page 2 of 3



CPF 1-2021-056-WL
you believe qualify for confidential treatment redacted and an explanation of why you believe the
redacted information qualifies for confidential treatment under 5 U.S.C. 552(b).
Sincerely,
Robert Burrough
Director, Eastern Region, Office of Pipeline Safety
Pipeline and Hazardous Materials Safety Administration
12021056WL_Warning Letter_08242021_(20-197118)_text Page 3 of 3

## Provenance

- Official: Yes
- Source: <https://primis.phmsa.dot.gov/enforcement-data/case/12021056WL>
- Source ID: `phmsa-enforcement`
- SHA-256: `056b4f5172d6671843662064b5eee9d8ddb525d24014b5d7d18c6d53fddd3519`
- Retrieved: 2026-08-20T04:44:44.458Z
- Exported: 2026-08-24T17:02:19.118Z
- Document slug: `phmsa-enforcement-12021056wl`

### Source metadata

```json
{
  "cpf": "12021056WL",
  "operator": "GILL RANCH STORAGE LLC",
  "region": "Eastern",
  "pipelineType": "INTRASTATE UNDERGROUND NG STORAGE",
  "caseStatus": "CLOSED",
  "citedSections": [
    "192.12(b)(2)"
  ],
  "dataAsOf": "08/04/2026 12PM",
  "caseDataAsOf": "2026-08-04",
  "attachmentCount": 2,
  "attachments": [
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      "name": "12021056WL_Warning Letter_08242021_(20-197118).pdf",
      "url": "https://primis.phmsa.dot.gov/enforcement-documents/12021056WL/12021056WL_Warning%20Letter_08242021_(20-197118).pdf",
      "bytes": 548426,
      "category": "agency_document"
    },
    {
      "name": "12021056WL_Warning Letter_08242021_(20-197118)_text.pdf",
      "url": "https://primis.phmsa.dot.gov/enforcement-documents/12021056WL/12021056WL_Warning%20Letter_08242021_(20-197118)_text.pdf",
      "bytes": 153834,
      "category": "agency_document"
    }
  ],
  "extractedAgencyDocumentCount": 1,
  "attachmentPolicy": "Official attachment links are retained. Agency-issued documents may also include a verified local PDF and page-level text representation.",
  "jurisdiction": "US",
  "operatorName": "GILL RANCH STORAGE LLC"
}
```
