SECOND MEASUREMENT SM-025

A pipeline operator must phone the National Response Center within an hour of confirming an incident. Since January 2024, for incidents with a death, injury, fire, explosion, major gas release or water pollution, 120 of 448 calls came later, by both the Center’s log and the operator’s own report

Markovian ProtocolMeasured 2026-10-24Status: published 2026-10-24; questions sent 2026-10-24DOI: 10.5281/zenodo.23620255

When a gas or oil pipeline has a reportable incident, federal rules give the operator one hour from “confirmed discovery” to telephone the National Response Center. In February 2026 the Pipeline and Hazardous Materials Safety Administration (PHMSA) reminded gas operators of the rule, after the National Transportation Safety Board investigated a fatal gas explosion in Dallas preceded by two related incidents the operator never reported. Each incident report an operator files with PHMSA gives its time of confirmed discovery and the number of its call to the Center, and the Center publishes when it received each call. We matched the two for the incidents reported from January 2024 to mid-October 2026. For the 448 incidents that were reportable on their face, with a death, an injury, a fire, an explosion, 3 million cubic feet of gas released or water polluted, 120 calls (26.8%) came more than an hour after confirmed discovery by the Center’s clock and by the operator’s own. Across all 924 calls we could match, including incidents reportable only once a cost estimate passed the threshold, 220 (23.8%) were late by both clocks, and 353 (38.2%) by the Center’s clock alone.

Disclosure: Markovian Protocol holds no financial position in any pipeline operator, was paid by no one for this work, and showed it to no one before publication. PHMSA gets the questions on publication. How we work.

By system

Incidents dated 1 January 2024 onward in PHMSA’s bulk files of 14 October 2026 (1,299 reports). “Late”: the Center received the call more than 65 minutes after confirmed discovery, the operator’s own form puts its call more than 60 minutes after, and the call’s text cites no cost or volume threshold. “Reportable on their face”, from the final form: a death, an injury, a fire or explosion, at least 3,000 thousand cubic feet of gas released unintentionally, or (liquid) water contamination. Not counted: 332 hazardous liquid reports marked “NRC notification not required”; the 4 marked “required but not made”; 2 with no number or no discovery time; and 37 whose number we could not tie to the same incident in the Center’s logs (16 not in the logs, 6 in another state, 10 with an incident date more than two days from both the PHMSA incident and its discovery, 2 with discovery dated more than a day before the incident, 3 where the log shows an earlier related call the form does not name). Nine forms gave the number of an update or correction; we followed it to the first call, which credits an operator whose first call reported a potential release before the source was confirmed. The Center’s times are Eastern: converted to each report’s time zone (Arizona without daylight time), 805 of the 924 agree with the operator’s own call time to within ten minutes.

Two clocks and a threshold

Operators’ own call times run slightly ahead of the Center’s: 220 forms put the call up to ten minutes before the Center logged receiving it, 27 up to ten minutes after. That is why the Center’s clock alone finds 353 late and the operators’ own forms 326: 37 calls are late by the Center’s receipt time but not by the form, 10 the other way. A five-minute allowance on the Center’s clock leaves 313. Late by both clocks: 291.

71 of those 291 calls say, in the Center’s record of the call, that the operator was reporting because a cost or volume estimate had crossed the reporting line, or that it had only now determined the event was reportable: “it met the PHMSA criteria for notification today … for damage amount”; “received notification today at 1500 that the cost to cleanup exceeds $50,000”; “took the two days since the release to estimate the damage amount”. For those, the time on the form may be when the release was confirmed, not when it became reportable; the rule’s “even if only based on a preliminary evaluation” cuts the other way. We leave them out of the 220 and list every one in rows_2026-10-24.csv (threshold_language), with the Center’s text.

The same doubt applies, without the wording, to incidents that were reportable only because of cost or the operator’s judgment: mostly small spills to soil and small gas releases, where the time on the form may be when the leak was found and the call came when the cleanup estimate passed $50,000. 100 of the 220 late calls are of that kind. That is why the headline uses only the 448 incidents reportable on their face, where a death, an injury, a fire, an explosion, a release of 3 million cubic feet or polluted water leaves no question that the event was reportable when it was discovered: 120 of those calls were late.

924 calls. 116 came in the ten minutes up to the hour. “Before the stated discovery”: 11 within 15 minutes, 46 more than 15 minutes before. Most of the 46 were calls made before the operator had confirmed a source, including ten about gas bubbling in the Gulf of Mexico; the rest suggest the field is sometimes entered loosely. Of the 65 more than a day after discovery, 26 cite a threshold in the call.

By operator

Operators with five or more counted calls and four or more late, as each report names the operator; affiliated companies that file under separate names are listed separately. The time is the confirmed discovery each operator entered on its own report. Most late calls by the liquid operators at the top, Colonial, Energy Transfer, Enterprise, Plains and Buckeye, were small spills reportable only once cleanup cost passed $50,000, which is where the form’s discovery time is least certain; the column “reportable on their face” shows how many were not. Every operator with five or more calls is in summary_2026-10-24.json, and every call, with the Center’s text, in rows_2026-10-24.csv.

Why the hour matters

The call is the first notice of an incident to federal authorities. In Dallas in February 2018 the gas operator investigated two incidents in the two days before a fatal explosion and reported neither, sending the state regulator a courtesy email after the second, according to PHMSA’s bulletin citing NTSB’s report.³ NTSB asked PHMSA to require reporting even before the source of the gas is known (recommendation P-21-1, February 2021).² The bulletin that addresses it came five years later and says its contents “do not have the force and effect of law”.³

PHMSA does enforce the hour. In October 2024 it issued Transwestern Pipeline, an Energy Transfer subsidiary, a notice of probable violation for four calls in 2020 to 2022 made 1.75 to 7 hours after the company identified the incidents, with a proposed penalty of $25,300 for that item.⁴ Those were found on inspection years later. The same evidence for every incident is in PHMSA’s own files and the Center’s public logs.

How this ends

PHMSA can close it: by comparing the call time with confirmed discovery on each incident report as it arrives, a comparison its own files already support, and by following up the late ones. We recheck quarterly against new reports and the Center’s logs, and print the shares here.

Our questions

Sent on 24 October to PHMSA’s Office of Pipeline Safety, through the contact named on the February 2026 bulletin. Answers will be printed here as written.

1. Does PHMSA compare the National Response Center call time with the confirmed discovery time on incident reports when they arrive, or only during inspections?
2. How many enforcement cases opened since January 2024 cite § 191.5(a) or § 195.52(a) for a late or missing call?
3. Four reports since 2024 say the call was “required but not made”. Was each followed up?
4. When an incident becomes reportable only once a cost estimate crosses the threshold, which time should the operator enter as confirmed discovery?
5. Does PHMSA consider the February 2026 advisory bulletin its full response to NTSB recommendation P-21-1?

Their reply, scored

What we can’t be sure of

• “Confirmed discovery” is the operator’s own time, and operators seem to enter it differently: some the moment the release was confirmed, some the moment it became reportable. The headline uses only incidents reportable on their face for that reason, and leaves out calls whose text cites a threshold; that text match on the Center’s records is approximate (in a sample of 40 it flagged, about one in ten did not cite a threshold).
• For hazardous liquid we count only reports with a call number; 332 marked the call “not required”, and we took that at its word. 65 of the liquid calls we count meet none of 195.52(a)(1) to (4) on the final form values and may have been made under (a)(5), the operator’s judgment, or voluntarily; leaving them out gives 205 of 859 late (23.9%), the same share. None of them is in the 448 reportable on their face.
• Each count rests on matching the report number on the PHMSA form to the Center’s log. We drop 37 matches that disagree on state or date or are ambiguous, and follow update and correction numbers to the first call. A wrong number that happens to agree on state and date would still be counted.
• Time zones: an incident near a zone boundary reported in the wrong zone would be off by an hour; the two-clock requirement guards against most of these.
• One snapshot: PHMSA’s files of 14 October 2026; reports from 2026 can still be added or revised.

Run it yourself

python3 analyze.py exhibits summary.json rows.csv

Python 3 with openpyxl. The PHMSA files come from PHMSA’s incident data page (its site refuses scripted downloads; we fetched them in a browser) and the call logs from nrc.uscg.mil; both are in sm-025/exhibits/ as downloaded, with SHA256SUMS. Script: analyze.py.

References

1. 49 CFR 191.3, 191.5, 195.2, 195.52, eCFR as of 22 October 2026, saved copies in sm-025/exhibits/; the April 2026 final rule (FR 2026-08057, effective 3 August) that removed electronic notice from 191.5(b) and left the hour unchanged. Every counted call is logged by the Center as a telephone call.
2. NTSB safety recommendation letter P-21-001 to -014, February 2021, and accident report PAR-21/01, Atmos Energy Corporation Natural Gas-Fueled Explosion, Dallas, Texas, February 23, 2018. Saved copy ntsb_P-21-001-014_letter.pdf.
3. PHMSA Advisory Bulletin ADB-2026-04, Pipeline Safety: Incident Notifications to the National Response Center, Federal Register 2026-03361, 20 February 2026; and ADB-2013-01 (2013-01958). Saved copies in sm-025/exhibits/.
4. PHMSA, Notice of Probable Violation, Proposed Civil Penalty and Proposed Compliance Order, CPF 4-2024-037-NOPV, Transwestern Pipeline Company, 4 October 2024. Saved copy phmsa_nopv_42024037_transwestern.pdf.
5. PHMSA, Distribution, Transmission & Gathering, LNG, and Liquid Accident and Incident Data (bulk files, January 2010 to present); National Response Center FOIA call files CY2024 to CY2026, nrc.uscg.mil.