Hazmat
in Motion

Form 5800.1 sorts every release into four boxes: highway, air, rail, water. Highway takes almost nine filings in ten, because that is where the shipments are. Read the second column, though, and the ranking flips - when a rail load gets loose, it turns serious at over five times the highway rate. One is a drum on a loading dock; the other is a tank car.

Bars share one scale. "Serious / 100" is serious incidents per 100 reported - rail runs 22 to highway's 4. Illustrative stand-in figures.

Read each mode across three ledgers and the ranking rearranges itself. Highway owns the paperwork: 87 of every 100 filings. But follow the lines right and rail - four filings in 100 - climbs to a fifth of the serious incidents and nearly a third of the dollar damage. A drum leaks by the gallon; a tank car breaches by the ton.

The same shares, as a table

Mode	Incidents	Serious	Damage
Highway	86.5%	69.6%	60.0%
Air	8.4%	8.6%	4.9%
Rail	4.1%	18.8%	31.9%
Water	1.0%	3.0%	3.2%

The map is a freight map wearing a warning color. Releases pool where the petrochemical corridors run - Texas and the Gulf, the industrial Midwest, the port-and-turnpike Northeast - and thin out across the intermountain West. Read it honestly: this is raw count, so it tracks where hazmat moves at least as much as where it is mishandled.

Top states, as a table

State	Incidents	Serious
Texas	2,760	138
California	2,180	109
Illinois	1,490	75
Ohio	1,210	61
Pennsylvania	1,020	51
New Jersey	960	48

Reported incidents per state in the reference year, single-hue density ramp, darker is more. Illustrative stand-in counts shaped to the real geography.

The leaderboard reads like a hardware store with a chemistry aisle: gasoline, lye, paint, battery acid. These are the workhorse chemicals of an industrial economy, and they spill at the rate they ship. The column to watch is the serious rate - the toxic gases at the bottom of the count, chlorine and anhydrous ammonia, turn serious two to three times as often as anything above them.

"Serious rate" = share of that commodity's incidents meeting PHMSA's serious threshold (a fatality, major injury, evacuation, closure, or large release). Illustrative stand-in figures.

Put every commodity on two axes at once and the board splits. The busy right edge is the everyday spill: gasoline leaks two thousand times a year and almost never hurts anyone. The upper left is the other story - chlorine gets loose barely two hundred times, and one release in five turns serious. The materials worth fearing are not the ones filed most often.

Highway is the default; the exceptions tell you what the material is. Fuels barely leave the truck. Lithium-ion batteries ride the parcel networks, so two releases in five happen in air cargo. And the bulk chemicals of the toxic-gas trade - ammonia, chlorine - move by tank car, which is exactly where their worst days happen.

The full mix, as a table

Commodity	Highway	Rail	Air	Water
Diesel fuel	95%	2%	0%	3%
Gasoline	93%	3%	0%	4%
Sodium hydroxide	88%	8%	1%	3%
Adhesives	84%	2%	13%	1%
Sulfuric acid	82%	13%	0%	5%
Anhydrous ammonia	74%	21%	0%	5%
Lithium-ion batteries	58%	1%	39%	2%
Chlorine	55%	40%	0%	5%

Filings are up roughly 48% over fifteen years - more freight, wider reporting, and a battery in every parcel. The serious count refuses to follow. It holds near a constant floor through the whole climb, which means almost all of the growth is minor spills that now make it onto a form. The paperwork is exploding; the catastrophe is not.

Spills follow the freight calendar and the thermometer. Reports climb through spring, peak in July - heat swells drums, softens seals, and raises vapor pressure in every tank - and ease off into winter. The serious count, once again, barely notices: catastrophe keeps its own schedule.

The register of failure is mundane. A cap not torqued, a fitting worked loose, a drum dropped off a forklift - human hands and tired hardware account for most of the file. The vehicle accident, the image everyone carries, sits near the bottom of the count - and at the top of the consequence column: when a release starts with a crash or a derailment, better than one in three turns serious.

This is the dek's promise made literal. Start with every form filed in a year and follow the consequence down: most reports are a weeping drum on a dock, found and contained. Each escalation - a release, a fire, an injury, a death - is roughly an order of magnitude rarer than the one before it. The catastrophe is real. It is also 1 filing in 1,923.

Bar length is on a base-10 log scale so each tier stays visible; the counts are the honest measure. Illustrative stand-in figures.

Compare tool Put two materials side by side Mode mix, serious rate, and volume for any two of the top commodities - shared scales, no invented numbers. ->