It Was Growing the Whole Time

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Seven years ago today, a tower at one of the biggest petrochemical complexes in the country tore itself open and threw a fireball 900 feet into the Texas sky. Thirty-seven people were hurt. Nobody died — which, when you see the size of it, is close to a miracle. And the thing that ruptured that line wasn’t a valve anyone missed or a gauge anyone misread. It was a byproduct that had been quietly growing inside the equipment, expanding with the force of a wedge, the whole time. Here’s the story, and the rule that says you have to know what your own process can make.

It was mid-morning, around 11:07, on a Wednesday. The Baytown complex sits on the Houston Ship Channel — one of the largest integrated refining and petrochemical sites in the United States, thousands of people on shift, a working city of pipe and steel with a residential town wrapped right around its fence line.

In the olefins plant, a unit processing propane and propylene let go. A line ruptured, the light hydrocarbons found their ignition, and the blast destroyed the tower and rolled up into a fireball reported at roughly 900 feet tall — one of the largest industrial explosions the Texas Gulf Coast has ever seen. The concussion was felt for miles. Harris County issued a shelter-in-place for the surrounding neighborhoods at about 11:15 a.m.; it wasn’t lifted until around 3 p.m., and the fire wasn’t fully out until close to 9:30 that night.

Thirty-seven people were injured — burns and minor injuries — and sixty-six were taken for medical evaluation. Here’s the part that stops you: not one person was killed. A 900-foot fireball at a crowded plant on a workday, and everybody went home. That is not because the hazard was small. It’s because the geometry and the timing happened to break in the workers’ favor, and it very easily could have gone the other way.

So what actually ruptured that line? After a three-week trial in 2023, a Harris County jury found ExxonMobil 100 percent responsible and awarded $28,591,000 to five workers hurt in the blast. The cause presented at trial was a buildup of something with a deceptively cute name: popcorn polymer.

Here’s the medicine, because it matters. In units running reactive light hydrocarbons — the diolefins you find in olefins and butadiene service — a hard, porous polymer can seed inside the piping and then grow on its own, autocatalytically, feeding its own reaction. It doesn’t just sit there. It expands with real mechanical force, packing itself into low-flow spots and dead legs, plugging and deforming pipe and vessels from the inside — and it can grow until it splits the steel open. It does its growing in the dark, in the parts of the system nobody’s looking at. The plaintiffs put on evidence that the hazard of popcorn polymer had been understood in industry for decades. The material didn’t sneak up on chemistry. It grew inside equipment that wasn’t being inspected or maintained for it.

This is 29 CFR 1910.119 — Process Safety Management of Highly Hazardous Chemicals — top to bottom.

PSM says, first, that you compile process safety information: you have to actually understand the hazards of what you’re running, including the reactive and self-generating ones — the byproduct your process makes, not just the product you sell. Second, mechanical integrity: safety-critical equipment gets inspected, tested, and maintained on a schedule, so a line doesn’t quietly pack solid and rupture. The OSHA investigation that followed the Baytown fire found neglected equipment, gaps in maintenance and inspection, and training shortfalls — and OSHA cited ExxonMobil, with penalties reported around $165,000. On the floor, PSM is the difference between “we clear that plugged line every so often, it’s just how that unit runs” and “a line that keeps plugging is the process telling us something is growing in there — stop and find out what.”

The whole spine of this newsletter is in that distinction. The people closest to that unit almost certainly knew that line gave them trouble. Whether that knowledge turned into a work order and an engineering fix, or just got absorbed into the daily grind as “normal,” is a leadership question — not a worker one. HOP says it plainly: normal is not the same as safe, and the buildup you’ve learned to live with is the one that gets you.

Most incidents are E, H, and S at once, and a 900-foot fireball in a residential-industrial community is a clean example. (S) The safety toll was 37 injured and a tower destroyed in one of the largest industrial blasts in Gulf Coast history — with the sobering asterisk that only luck kept the fatality count at zero. (H) Acute health was burns and blast injuries to those 37, plus 66 sent for evaluation; beyond the fence, a whole community was ordered to shelter in place under a plume of black smoke, and a fenceline neighborhood breathing petrochemical combustion products is an acute respiratory-exposure question no matter what the final numbers say. (E) The environment took the plume directly: heavy black smoke and particulate over Baytown, a shelter-in-place, and a community air-pollution lawsuit that followed. Texas’ TCEQ deployed to monitor and reported it did not detect contaminants of concern at the perimeter — I’ll give you that straight rather than dress it up — but the Baytown complex operates under Clean Air Act permits and has a long, documented history of emissions violations, and any facility running flammables above threshold quantities lives under EPA’s Risk Management Program, with firewater runoff a Clean Water Act concern. One un-inspected line that let a polymer grow was a safety failure, a community health event, and an air-quality event in the same ten seconds — it just depended which side of the fence you were standing on.

On May 27, 2026, the Chemical Safety Board released its final report on the November 12, 2024 explosion at the Givaudan Sense Colour caramel-coloring plant in Louisville, Kentucky, which killed two workers and seriously injured three. A 2,500-gallon reactor went into a runaway decomposition reaction with the sugar it was cooking; the pressure spike blew past the emergency relief system and split the vessel. The CSB found the relief system would have needed to be about four times larger to handle the reaction that chemistry could actually produce — and that the control room where the two men died sat just 40 feet from the reactor and wasn’t built to survive a blast. The reactor shell was thrown 245 feet into a neighborhood. So what for safety leaders: your relief system is sized for the reaction you assumed, and your control room is where you put it — both are only as good as your understanding of the worst case. The CSB renewed its long-standing call for OSHA to expand PSM to cover reactive hazards and for EPA to address them under RMP. Same root as Baytown: the hazard was knowable; the question is whether anyone ran it down before the steel did.

On June 2, 2026, the CSB urged chemical facilities to prepare now, with the Atlantic season running through November 30 and its worst months still ahead. Their reminder came with receipts: Arkema Crosby in Hurricane Harvey (2017), where flooded refrigeration let organic peroxides decompose and burn after backup power failed; and Bio-Lab in Lake Charles during Hurricane Laura (2020), where a torn roof let rainwater reach a million-plus pounds of reactive pool chemical and pushed a chlorine plume over Interstate 10. So what: even a “below-normal” forecast is a single storm away from a catastrophe if one facility isn’t ready. The four priorities are unglamorous and they work — secure your hazardous materials, guarantee backup power for safety-critical systems, train people on the emergency plan, and coordinate with your local responders before a storm has a name. If you sit on the Gulf, this is a this-week job, not an October one.

Shared blamelessly, so the next crew doesn’t learn it the hard way.

A unit at a petrochemical plant had a transfer line that plugged up now and then — always in the same spot. The crew had a routine for it: isolate, clear it, get it back in service, move on. It was just a known quirk of that line. One shift, a newer operator asked the question nobody had asked out loud in a while — why does it keep plugging in the exact same place? The lead could’ve brushed it off; instead he pulled the thread. They looped in a process engineer, cut into the section during the next turnaround, and found the line packing itself solid with a hard polymer buildup — the kind that grows under its own reaction and can build a pressure it was never designed to hold. It wasn’t a clog. It was a slow-motion rupture that hadn’t happened yet.

Here’s the blameless read, because it matters. Nobody on that crew was careless — they had a repeatable procedure and it worked every time, which is exactly what made the hazard invisible. “We just clear it when it plugs” is a totally reasonable habit right up until you learn what is doing the plugging. The save didn’t come from anyone being tougher or more diligent; it came from a culture where a green operator could ask “why” without getting told to just do the job, and a lead who treated a nagging recurring problem as information instead of annoyance. The fix isn’t “try harder.” It’s designing the question in: a recurring plug, a line that keeps fouling, a valve that keeps sticking — those are your process talking. Root-cause the nuisance before the nuisance roots you.

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Pick one recurring “quirk” on your unit today — the line that always plugs, the exchanger that always fouls, the valve that always sticks — and ask the Baytown question out loud: do we actually know what’s causing it, or have we just built a routine around it? If the honest answer is that you clear it and move on without knowing the mechanism, that’s not a nuisance. That’s a hazard you’ve learned to live with. Write the work order, pull in someone who can look inside, and find out what’s growing in the dark before it decides to show you.

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Please stay Safe & Hydrated!!!