kvlak limn

Transportation & Safety / PHMSA Pipeline Safety

What the Pipeline Spilled

Ledger of record: PHMSA incident and accident flagged files / one row per filed report / 1986-2024

Every time a pipeline in America fails hard enough to matter, somebody has to write it down: the barrels lost, the dollars burned, the people hurt. Four decades of those filings sit in one federal ledger. This page reads it straight - who spilled, what the pipe carried, how big the spills really run, and the distance between an incident that is significant and one that is serious. The two words are doing very different jobs, and the gap between them is where the truth about pipeline risk lives.

RATE ~600 significant incidents / yr
VOL 2.5M barrels lost, span total
LIFE 442 deaths on record
COST $34.7B property damage
Illustrative PHMSA Pipeline Safety - Incident & Accident Flagged Files / 1986-2024
ST-01 / GEOGRAPHY

Where the Line Fails

Significant incidents by state, 1986-2024

Pipelines follow oil and gas, and so do their failures. Each state is shaded by the count of significant incidents filed there since 1986. Texas, sitting on the densest network of pipe in the country, out-fails every other state by nearly three to one - not because Texas pipe is worse, but because there is simply more of it to fail. The barrels tell the same geography harder: of the roughly 2,479 thousand net barrels lost across the span, the crude-oil corridor from the Gulf up through Kansas holds most of the stain.

Alabama: 335 significant incidents, 33,165 bbl lost, 7 deaths Alaska: 235 significant incidents, 38,775 bbl lost, 5 deaths Arizona: 195 significant incidents, 13,942 bbl lost, 4 deaths Colorado: 430 significant incidents, 54,394 bbl lost, 9 deaths Florida: 205 significant incidents, 12,402 bbl lost, 4 deaths Georgia: 350 significant incidents, 23,100 bbl lost, 7 deaths Indiana: 470 significant incidents, 43,945 bbl lost, 10 deaths Kansas: 780 significant incidents, 111,540 bbl lost, 16 deaths Maine: 58 significant incidents, 3,828 bbl lost, 1 deaths Massachusetts: 128 significant incidents, 7,744 bbl lost, 3 deaths Minnesota: 390 significant incidents, 42,900 bbl lost, 8 deaths New Jersey: 360 significant incidents, 25,740 bbl lost, 8 deaths North Carolina: 320 significant incidents, 21,120 bbl lost, 7 deaths North Dakota: 240 significant incidents, 36,960 bbl lost, 5 deaths Oklahoma: 1,250 significant incidents, 192,500 bbl lost, 26 deaths Pennsylvania: 600 significant incidents, 46,200 bbl lost, 13 deaths South Dakota: 82 significant incidents, 9,020 bbl lost, 2 deaths Texas: 4,200 significant incidents, 693,000 bbl lost, 88 deaths Wyoming: 460 significant incidents, 68,310 bbl lost, 10 deaths Connecticut: 108 significant incidents, 6,534 bbl lost, 2 deaths Missouri: 420 significant incidents, 34,650 bbl lost, 9 deaths West Virginia: 265 significant incidents, 24,777 bbl lost, 6 deaths Illinois: 700 significant incidents, 73,150 bbl lost, 15 deaths New Mexico: 450 significant incidents, 66,825 bbl lost, 9 deaths Arkansas: 285 significant incidents, 34,485 bbl lost, 6 deaths California: 1,500 significant incidents, 140,250 bbl lost, 32 deaths Delaware: 40 significant incidents, 2,640 bbl lost, 1 deaths District of Columbia: 16 significant incidents, 880 bbl lost, 0 deaths Hawaii: 26 significant incidents, 1,430 bbl lost, 1 deaths Iowa: 245 significant incidents, 24,255 bbl lost, 5 deaths Kentucky: 300 significant incidents, 26,400 bbl lost, 6 deaths Maryland: 138 significant incidents, 9,108 bbl lost, 3 deaths Michigan: 520 significant incidents, 45,760 bbl lost, 11 deaths Mississippi: 345 significant incidents, 45,540 bbl lost, 7 deaths Montana: 215 significant incidents, 29,562 bbl lost, 5 deaths New Hampshire: 44 significant incidents, 2,662 bbl lost, 1 deaths New York: 540 significant incidents, 32,670 bbl lost, 11 deaths Ohio: 620 significant incidents, 47,740 bbl lost, 13 deaths Oregon: 148 significant incidents, 10,582 bbl lost, 3 deaths Tennessee: 275 significant incidents, 21,175 bbl lost, 6 deaths Utah: 165 significant incidents, 19,965 bbl lost, 3 deaths Virginia: 255 significant incidents, 16,830 bbl lost, 5 deaths Washington: 310 significant incidents, 27,280 bbl lost, 7 deaths Wisconsin: 235 significant incidents, 18,095 bbl lost, 5 deaths Nebraska: 185 significant incidents, 21,367 bbl lost, 4 deaths South Carolina: 158 significant incidents, 10,428 bbl lost, 3 deaths Idaho: 88 significant incidents, 7,744 bbl lost, 2 deaths Nevada: 96 significant incidents, 6,864 bbl lost, 2 deaths Vermont: 20 significant incidents, 1,210 bbl lost, 0 deaths Louisiana: 1,180 significant incidents, 188,210 bbl lost, 25 deaths Rhode Island: 28 significant incidents, 1,540 bbl lost, 1 deaths
Shade = significant incidents per state, 1986-2024, five quantile classes on the validated spill ramp. Alaska and Hawaii are inset by the Albers USA projection; territories fall outside its frame and appear only in the table. illustrative
Most incidents
  1. 01 Texas 4,200
  2. 02 California 1,500
  3. 03 Oklahoma 1,250
  4. 04 Louisiana 1,180
  5. 05 Kansas 780
Every state, in a table
State Incidents Barrels lost Damage $M Deaths
Texas TX 4,200 693,000 8,190 88
California CA 1,500 140,250 2,242.5 32
Oklahoma OK 1,250 192,500 2,350 26
Louisiana LA 1,180 188,210 2,259.7 25
Kansas KS 780 111,540 1,411.8 16
Illinois IL 700 73,150 1,095.5 15
Ohio OH 620 47,740 861.8 13
Pennsylvania PA 600 46,200 834 13
New York NY 540 32,670 693.9 11
Michigan MI 520 45,760 759.2 11
Indiana IN 470 43,945 702.7 10
Wyoming WY 460 68,310 848.7 10
New Mexico NM 450 66,825 830.2 9
Colorado CO 430 54,394 733.1 9
Missouri MO 420 34,650 598.5 9
Minnesota MN 390 42,900 624 8
New Jersey NJ 360 25,740 487.8 8
Georgia GA 350 23,100 462 7
Mississippi MS 345 45,540 600.3 7
Alabama AL 335 33,165 512.5 7
North Carolina NC 320 21,120 422.4 7
Washington WA 310 27,280 452.6 7
Kentucky KY 300 26,400 438 6
Arkansas AR 285 34,485 475.9 6
Tennessee TN 275 21,175 382.2 6
West Virginia WV 265 24,777 396.2 6
Virginia VA 255 16,830 336.6 5
Iowa IA 245 24,255 374.9 5
North Dakota ND 240 36,960 451.2 5
Wisconsin WI 235 18,095 326.6 5
Alaska AK 235 38,775 458.2 5
Montana MT 215 29,562 381.6 5
Florida FL 205 12,402 263.4 4
Arizona AZ 195 13,942 264.2 4
Nebraska NE 185 21,367 302.5 4
Utah UT 165 19,965 275.6 3
South Carolina SC 158 10,428 208.6 3
Oregon OR 148 10,582 200.5 3
Maryland MD 138 9,108 182.2 3
Massachusetts MA 128 7,744 164.5 3
Connecticut CT 108 6,534 138.8 2
Nevada NV 96 6,864 130.1 2
Idaho ID 88 7,744 128.5 2
South Dakota SD 82 9,020 131.2 2
Maine ME 58 3,828 76.6 1
New Hampshire NH 44 2,662 56.5 1
Delaware DE 40 2,640 52.8 1
Rhode Island RI 28 1,540 35 1
Hawaii HI 26 1,430 32.5 1
Vermont VT 20 1,210 25.7 0
District of Columbia DC 16 880 20 0
OP-02 / LEDGER

Who Spilled the Most

Top operators by net barrels lost

Ranked by net barrels lost - what was released and never recovered. The crude and NGL haulers own this ledger, and they should: they move the most liquid through the most pipe. Watch the bottom of the list instead. Two gas utilities sit there with zero barrels and the worst death tolls on the page, because gas does not spill - it finds a basement and waits for a spark. Bars share one scale; length is the comparison.

  1. 01
    Plains All American Pipeline Crude
    412,000 bbl 720 incidents $610M damage 2 deaths
  2. 02
    Enbridge (Lakehead System) Crude
    340,000 bbl 430 incidents $690M damage 1 death
  3. 03
    Enterprise Products (Crude & NGL) HVL/NGL
    318,000 bbl 640 incidents $540M damage 3 deaths
  4. 04
    Energy Transfer / Sunoco Pipeline Crude
    286,000 bbl 590 incidents $505M damage 4 deaths
  5. 05
    Marathon Pipe Line Crude
    224,000 bbl 470 incidents $398M damage 2 deaths
  6. 06
    Colonial Pipeline Refined
    206,000 bbl 300 incidents $455M damage 3 deaths
  7. 07
    ExxonMobil Pipeline Crude
    178,000 bbl 360 incidents $405M damage 1 death
  8. 08
    Magellan Pipeline Refined
    168,000 bbl 510 incidents $352M damage 1 death
  9. 09
    Kinder Morgan (SFPP & CO2) Refined
    152,000 bbl 480 incidents $338M damage 2 deaths
  10. 10
    Phillips 66 Pipeline Refined
    141,000 bbl 395 incidents $296M damage 2 deaths
  11. 11
    Chevron Pipe Line Crude
    133,000 bbl 320 incidents $284M damage 1 death
  12. 12
    ONEOK NGL Pipeline HVL/NGL
    126,000 bbl 300 incidents $240M damage 2 deaths
  13. 13
    Shell Pipeline Crude
    121,000 bbl 280 incidents $258M damage 1 death
  14. 14
    Buckeye Partners Refined
    118,000 bbl 340 incidents $262M damage 1 death
  15. 15
    Pacific Gas & Electric Gas trans.
    no spill volume - gas system
    0 bbl 210 incidents $880M damage 10 deaths
  16. 16
    Atmos Energy Gas dist.
    no spill volume - gas system
    0 bbl 340 incidents $410M damage 17 deaths

Barrels are net loss (released minus recovered). Operator totals span mergers and name changes. illustrative

OP-03 / CROSSCHECK

Barrels Are Not Bodies

Net barrels lost vs deaths, per operator

Cross the two ledgers and they refuse to agree. The crude haulers that top the volume ranking sit along the floor of this chart: hundreds of thousands of barrels, one or two deaths each. The two gas utilities sit pinned to the left wall - zero barrels, ever, and 27 of the 53 deaths among these sixteen operators. A barrel count measures the mess. It does not measure the harm.

0 5 10 15 0100k200k300k400k net barrels lost, span total deaths Plains All American Pipeline: 412,000 bbl lost, 2 deaths, 720 incidents Plains All American Enbridge (Lakehead System): 340,000 bbl lost, 1 death, 430 incidents Enterprise Products (Crude & NGL): 318,000 bbl lost, 3 deaths, 640 incidents Enterprise Products Energy Transfer / Sunoco Pipeline: 286,000 bbl lost, 4 deaths, 590 incidents Energy Transfer Marathon Pipe Line: 224,000 bbl lost, 2 deaths, 470 incidents Colonial Pipeline: 206,000 bbl lost, 3 deaths, 300 incidents Colonial ExxonMobil Pipeline: 178,000 bbl lost, 1 death, 360 incidents Magellan Pipeline: 168,000 bbl lost, 1 death, 510 incidents Kinder Morgan (SFPP & CO2): 152,000 bbl lost, 2 deaths, 480 incidents Phillips 66 Pipeline: 141,000 bbl lost, 2 deaths, 395 incidents Chevron Pipe Line: 133,000 bbl lost, 1 death, 320 incidents ONEOK NGL Pipeline: 126,000 bbl lost, 2 deaths, 300 incidents Shell Pipeline: 121,000 bbl lost, 1 death, 280 incidents Buckeye Partners: 118,000 bbl lost, 1 death, 340 incidents Pacific Gas & Electric: 0 bbl lost, 10 deaths, 210 incidents Pacific Gas & Electric Atmos Energy: 0 bbl lost, 17 deaths, 340 incidents Atmos Energy
Liquid systems (crude, refined, HVL) Gas systems
Sixteen operators, span totals: net barrels lost against deaths. Gas systems report no barrels by definition, so their dots sit on the zero line - the volume ledger cannot see them at all. illustrative
Every operator, in a table
OperatorSystemBarrels lostDeathsInjuries
Plains All American Pipeline Liquid 412,000 2 9
Enbridge (Lakehead System) Liquid 340,000 1 7
Enterprise Products (Crude & NGL) Liquid 318,000 3 14
Energy Transfer / Sunoco Pipeline Liquid 286,000 4 11
Marathon Pipe Line Liquid 224,000 2 8
Colonial Pipeline Liquid 206,000 3 5
ExxonMobil Pipeline Liquid 178,000 1 6
Magellan Pipeline Liquid 168,000 1 6
Kinder Morgan (SFPP & CO2) Liquid 152,000 2 10
Phillips 66 Pipeline Liquid 141,000 2 7
Chevron Pipe Line Liquid 133,000 1 5
ONEOK NGL Pipeline Liquid 126,000 2 9
Shell Pipeline Liquid 121,000 1 4
Buckeye Partners Liquid 118,000 1 8
Pacific Gas & Electric Gas 0 10 58
Atmos Energy Gas 0 17 71
SP-04 / THE SPLIT

Significant Is Not Serious

Recent 10-year annual average

The regulator counts in nested tiers, and the words are doing precise work. Significant is the wide net: a fire, a big enough spill, fifty thousand 1984 dollars of damage. Serious is the narrow one: a death or a hospitalization. Out of roughly seven hundred significant incidents a year, about one in fourteen hurts a person badly enough to count. Quote the big number as if it measured bodies and you inflate the toll fourteen-fold; quote only the deaths and you hide how often the line actually lets go. The page holds both numbers apart on purpose.

All reported incidents 1,160/yr

Every incident meeting PHMSA's reporting criteria that year.

Significant 682/yr
59% of prior

Death, injury needing hospitalization, fire/explosion, >=5 bbl HVL or >=50 bbl liquid, or >=$50k (1984 dollars).

Serious 48/yr
7% of prior

A fatality or an injury requiring in-patient hospitalization.

Fatal 12/yr
25% of prior

At least one death. A subset of serious.

TR-05 / TREND

The Line Climbs, the Deaths Do Not

1986-2024

Significant incidents rose about 93% across the span, from roughly 360 a year to 696. Some of that is more pipe in the ground; a lot of it is a wider net - the 2002 and 2010 rule revisions, pinned on the chart, both changed what operators must report. The serious count, the line hugging the floor, barely moved in four decades. The system files more paperwork than it used to. It does not kill more people than it used to.

0 175 350 525 700 19901995200020052010201520202024 2002 rule 2010 rule 696 significant 53 serious
Significant incidents Serious (a death or a hospitalization)
Significant and serious incidents filed per year, 1986-2024. Vertical pins mark the 2002 and 2010 reporting-rule revisions, which widened what counts. The serious tier is a subset of the significant tier. illustrative
Year-by-year, in a table
YearSignificantSeriousDeathsBarrels lost
1986 360 27 10 90,000
1987 375 30 13 101,585
1988 388 33 15 110,926
1989 399 35 15 116,278
1990 407 36 14 116,784
1991 411 37 11 112,666
1992 412 36 8 105,174
1993 412 35 6 96,308
1994 412 34 22 88,374
1995 412 32 6 83,472
1996 415 30 18 83,027
1997 421 29 11 87,471
1998 431 28 14 96,148
1999 443 28 15 107,463
2000 457 28 15 119,231
2001 472 30 13 129,168
2002 526 35 10 135,396
2003 539 37 7 136,863
2004 548 39 5 133,577
2005 553 42 5 126,602
2006 556 44 6 117,825
2007 556 46 9 109,532
2008 556 47 12 103,901
2009 556 48 14 102,521
2010 593 50 22 106,030
2011 597 50 14 113,983
2012 605 50 12 124,944
2013 616 49 9 136,807
2014 630 48 7 147,267
2015 645 47 5 154,330
2016 659 46 5 156,758
2017 672 46 7 154,345
2018 683 46 21 147,961
2019 690 46 13 139,361
2020 694 46 19 130,792
2021 695 47 15 124,494
2022 695 49 14 122,203
2023 695 51 11 124,762
2024 696 53 8 131,935
TR-06 / GAUGES

Same Years, Four Needles

Each panel on its own scale

Put the four measures side by side and only one of them trends. Significant incidents climb steadily. Serious incidents drift inside a narrow band. Deaths spike and fall with single catastrophes - 1994, 2010, 2018, 2020 - and never find a direction. Barrels swing on the price and flow of crude. Anyone quoting one of these lines as if it were the other three is telling you a story the ledger does not.

Four readings of the same yearly ledger, 1986-2024. Panels share the x axis but not the y scale; each panel's peak year sets its top gridline and is printed in its title. illustrative
ER-07 / ERAS

The Ledger Tilts Toward Gas

Significant incidents by decade and system

Stack each decade of the ledger and split it by what the failing system carried. Two things move at once: every decade is bigger than the last, and the gas share grows inside it - from about 44% of incidents in the first decade to 61% in the most recent band. Part of that is real (an aging distribution network under growing cities), part is definitional (gathering lines only entered broad reporting in 2022). Either way, the modern pipeline incident is more likely to be a gas leak than an oil spill.

0 2,000 4,000 6,000 1986-1995 44% gas 3,988 1996-2005 48% gas 4,805 2006-2015 53% gas 5,910 2016-2024 61% gas 6,179
Gas systems (distribution, transmission, gathering, LNG) Liquid systems (crude, refined, HVL)
Decade rollups of the yearly ledger (the last band covers nine years, 2016-2024). Bar length is total significant incidents on one shared scale; the printed percentage is the gas share of that decade. illustrative
The decades, in a table
DecadeGas incidentsLiquid incidentsTotalDeaths
1986-1995 1,755 2,233 3,988 120
1996-2005 2,306 2,499 4,805 113
2006-2015 3,134 2,776 5,910 110
2016-2024 3,773 2,406 6,179 113
CM-08 / COMMODITY

What the Pipe Carried

Incidents / barrels / deaths

Score each cargo three ways and the columns refuse to agree. Gas distribution leads on incidents and on deaths, yet registers not a single barrel - gas leaks and explodes, it does not pool. The volume ledger belongs to crude oil, which spills oceans and kills almost no one. Each bar is scaled to its own column's maximum; read down a column to rank the cargos, across a row to see one cargo's whole ledger.

Gas distribution Mains & service lines into homes. Few barrels, most of the deaths.
6,800
-
300
Crude oil Biggest spills by volume.
4,600
1,650,000
22
Gas transmission Large-diameter interstate gas lines.
3,200
-
95
Refined products Gasoline, diesel, jet fuel.
3,050
760,000
18
Highly volatile liquids / NGL Propane, ethane, anhydrous ammonia - flash to vapor.
2,600
540,000
24
Gas gathering Field lines from wells; reporting expanded 2022.
900
-
8
LNG facilities Liquefaction & storage plants.
180
-
3
CM-09 / SHARES

The Death Share Is Not the Spill Share

Share of incidents vs share of deaths

Take each commodity's slice of the incident ledger and follow it to its slice of the death ledger. Gas distribution - the small pipes under streets and into basements - files about 32% of significant incidents and takes 64% of the deaths. Every liquid line falls: crude oil is a fifth of the incidents and a twentieth of the deaths. The pipe that reaches your house is the one that kills.

Share of incidents Share of deaths Gas distribution 32% 64% Gas distribution Crude oil 22% 4.7% Crude oil Gas transmission 15% 20% Gas transmission Refined products 14% 3.8% Refined products HVL / NGL 12% 5.1% HVL / NGL Gas gathering 4.2% 1.7% Gas gathering LNG 0.8% 0.6% LNG
Gas systems Liquid systems
Each commodity's share of all significant incidents (left) and of all pipeline deaths (right), span totals. Labels nudged apart where values crowd; the thin connectors point back to the true position. illustrative
The shares, in a table
CommoditySystemIncidentsShareDeathsShare
Gas distribution Gas 6,800 32% 300 64%
Crude oil Liquid 4,600 22% 22 4.7%
Gas transmission Gas 3,200 15% 95 20%
Refined products Liquid 3,050 14% 18 3.8%
Highly volatile liquids / NGL Liquid 2,600 12% 24 5.1%
Gas gathering Gas 900 4.2% 8 1.7%
LNG facilities Gas 180 0.8% 3 0.6%
SZ-10 / SIZE

Most Spills Are Small. The Barrels Are Not.

Liquid systems, net barrels per incident

Sort every liquid-system incident by how much it actually released and the ledger splits in two. Three out of four spills stay under fifty barrels - a patch of ground, a cleanup crew, a filing. But the 7.8% of incidents that top five hundred barrels carry 85% of everything ever spilled. The typical incident is a puddle. The typical barrel is lost in a flood.

How often each size happens share of liquid incidents 42% under 5 bbl 4,300 spills 33% 5 to 50 bbl 3,400 spills 17% 50 to 500 bbl 1,750 spills 6.2% 500 to 5,000 bbl 640 spills 1.6% over 5,000 bbl 160 spills Where the barrels went share of all net barrels lost 12%41%44% 0.3% under 5 2.5% 5 to 50 2,479,193 bbl total
Five ordered size classes of net barrels lost per incident, liquid systems only (gas reports no barrels). Top: each class's share of incidents. Bottom: the same classes, same shades, as a share of total volume. illustrative
The size classes, in a table
Size classSpillsShare of spillsBarrels lostShare of barrels
under 5 bbl 4,300 42% 8,600 0.3%
5 to 50 bbl 3,400 33% 61,000 2.5%
50 to 500 bbl 1,750 17% 297,000 12%
500 to 5,000 bbl 640 6.2% 1,020,000 41%
over 5,000 bbl 160 1.6% 1,092,593 44%
CS-11 / CAUSE

Why the Line Lets Go

Share of incidents vs share of barrels

The backhoe gets the headlines; the rust gets the pipe. Corrosion and material or weld failure - metal quietly giving up - account for about 41% of significant incidents and an even larger cut of the volume. Excavation damage runs the other way: 14.5% of incidents but only 7.1% of the barrels, because a struck line is found in minutes while a corroded seam can bleed for days. The dominant pipeline hazard is not an accident. It is age.

Share of significant incidents Share of net barrels lost
Material / weld / equipment failure 21.8% 24.4% Corrosion 19.7% 23.4% Other / unknown 15.4% 15.9% Excavation damage 14.5% 7.1% Incorrect operation 11.3% 12.9% Natural force damage 9.6% 10.2% Other outside force 7.7% 6.1%
Each cause's share of all significant incidents (dark bar) and of all net barrels attributed to a cause (orange bar), span totals, one shared scale. illustrative
The causes, in a table
CauseIncidentsShareBarrels lostShareNote
Material / weld / equipment failure 4,650 21.8% 720,000 24.4% Bad pipe, seams, or fittings.
Corrosion 4,200 19.7% 690,000 23.4% Internal & external metal loss - the slow killer of old steel.
Other / unknown 3,280 15.4% 470,000 15.9% Miscellaneous or undetermined.
Excavation damage 3,100 14.5% 210,000 7.1% A backhoe hits the line. Preventable.
Incorrect operation 2,400 11.3% 380,000 12.9% Human error in operating the system.
Natural force damage 2,050 9.6% 300,000 10.2% Earth movement, flooding, temperature.
Other outside force 1,650 7.7% 180,000 6.1% Vehicles, fire, vandalism, third parties.
MD-12 / METHOD

Methodology

Notes on the Data

The figures on this page follow PHMSA Pipeline Safety - Incident & Accident Flagged Files (1986-2024 reports (flagged files current through 2024)). PHMSA's "flagged files" are the bulk product the agency itself uses to build its twenty-year trends: every incident and accident report operators are required to file, plus the derived flags - significant, serious, and the harmonized cause categories - that let the records be compared across decades of changing report forms.

Illustrative Every number on this page is a stand-in until the real ingest runs.

What's real, what's a stand-in

This build is illustrative, and it says so on every figure. The numbers - the state map, the operator ledger and scatter, the yearly trend and gauges, the decade split, the commodity, share, size-class, and cause readings - are representative stand-ins, hand-authored to be internally consistent and to sit in the right order of magnitude (about ~600 significant incidents a year, the rate PHMSA reports). They are not a real ingest, and no chart here should be quoted as fact. The pipeline to make them real is built and documented: src/lib/source.ts declares the exact flagged-file column schema, scripts/build-data.ts aggregates raw rows into this exact shape - including the decade and spill-size slices - and HANDOFF.md lists the download steps. Dropping the real ZIPs into data/raw/ and running npm run data swaps every figure at the data layer with nothing else changed.

The words, precisely

Significant incidents meet at least one threshold: a fatality or in-patient hospitalization; a fire or explosion; 5 or more barrels of highly volatile liquid or 50 or more barrels of other liquid; or $50,000-plus in damage measured in 1984 dollars. Serious is the narrower tier - a death or a hospitalization - and is a subset of significant. "Barrels lost" is net loss: volume released minus volume recovered. Gas systems report no barrels, so their rows sit at zero volume by definition, not by omission - which is exactly why this page keeps crossing the volume ledger against the death ledger.

How the derived slices are cut

The decade bands roll up the yearly ledger (the last band covers nine years, 2016-2024) and split it by system type: distribution, transmission, gathering, and LNG count as gas; crude, refined products, and HVL count as liquid. The spill-size classes cover liquid systems only and bin each incident by its net barrels lost. Shares in the slope and cause charts are computed within their own slice's total, so each chart is internally consistent even where the hand-authored slices disagree with one another by a percent or two - a real ingest removes that slack.

What you're not seeing

Reporting thresholds have moved over time, so raw year-over-year counts mix real change with definitional change - the 2002 and 2010 rule revisions pinned on the trend chart both widened the net. Gas gathering lines were only broadly brought into reporting in 2022, so the deep history understates them and inflates the recent gas share. Operator names change with mergers and are reported as the operator of record at the time, so a single company can appear under several names across the span. And an incident is a reported release, not a measure of long-term environmental or health harm, which no single dataset captures.


Generated 2026-07-06 00:00 UTC. Source: PHMSA Pipeline Safety - Incident & Accident Flagged Files. Swap-point: src/lib/source.ts.