By Faye Flam / Bloomberg Opinion
If things had gone a bit differently, the chemicals on the train that derailed in East Palestine, Ohio, could have exploded, killing people on the spot, maybe hundreds. That’s the unacceptable risk thrust on communities across the country by the transportation of hazardous materials. Fixing the problem won’t be easy.
Investigations will no doubt follow into what operator Norfolk Southern did wrong. The White House has already pledged to hold the company accountable. But the only sure way to avoid future accidents is to stop transporting dangerous materials across vast distances — whether by train, car or pipeline — since they all present risks.
The explosion danger stems from the nature of several of the substances on the train, which derailed Feb. 3; in particular, vinyl chloride, a building block of plastics. It can only be transported as what’s called a pressurized liquid. If exposed to enough heat from a fire, the vinyl chloride can boil and build enough pressure to blow apart even the most powerfully reinforced container.
That’s what authorities feared would happen in East Palestine. The technical term for such a mega blast is a BLEVE, for Boiling Liquid Expanding Vapor Explosion, said chemist and toxicologist Hans Plugge, who heads the consulting firm Safer Chemical Analytics. You can try to quantify the power of a BLEVE in terms of 100s of tons of explosive, he said, but it comes across better if you watch a video of a disaster such as the 1983 BLEVE in Murdock, Illinois, which looked like an atomic blast and flung the remains of a tank car close to a mile away.
In East Palestine, a BLEVE was narrowly averted with a deliberate burning, sending up ugly black clouds of smoke, while the town was evacuated. The burn should have destroyed most of the vinyl chloride, but residents are still faced with concerns about long-term contamination with whatever leaked before the burn, as well as byproducts of the fire, including four other hazardous chemicals. Longer-lived contaminants called dioxins can form from incomplete combustion and tend to accumulate in the environment and people’s bodies.
And all for what? Vinyl chloride is a building block for polyvinyl chloride, or PVC; a plastic nobody loves. It’s used for pipes as well as cheap building materials and medical equipment. But ending the dangers posed by transporting the pressurized liquid is harder than just swearing off PVC. There are already greener alternatives, in some cases good old-fashioned natural building materials. The reason we have so much PVC and it’s so cheap is that it serves another purpose; using up chlorine that’s produced as a waste product in other processes.
The chemical industry makes a lot of chlorine because it’s a byproduct in the production of sodium hydroxide, used in everything from wastewater treatment to pharmaceuticals to making bicycles. Sodium hydroxide is made from water and ordinary salt, but it takes lots of energy and leaves behind tons of chlorine.
Chemical companies could pay to get rid of the chlorine, or they could find uses for it. Making chlorine-containing products, however, requires train compartments to be filled with pressurized chlorine gas, which is far more dangerous than vinyl chloride. So, making PVC is seen as the lesser of evils.
I talked to both chemists and activists about the solution. Everyone agrees that we need to make chemical transport safer and, because unexpected things can happen, the best way to do that is to reduce the transportation of hazardous substances in the first place. “No matter where the trains run, individuals are assuming risks they don’t know exist, risks that are thrust on them without their knowledge by others far removed from the hazard,” said chemist Mark Jones, a consultant who had worked in industry.
Jones sent me a diagram showing an elaborate tree with all the products needing sodium hydroxide as branches. The problem isn’t that people like PVC too much — we don’t — it’s that we like all that other stuff, and what that leaves us with is a lot of chlorine. The root of the problem then is not finding a substitute for PVC but finding ways to use up excess chlorine that doesn’t endanger people. “That’s where you get this weird mess of interrelated things,” Jones said.While the chloride ions that make up part of ordinary salt are stable, once an industrial process turns it into chlorine gas, it becomes reactive and potentially dangerous to human lungs. Chlorine gas was employed as a chemical weapon in World War I. Chlorine is a component in most of the “dirty dozen” chemicals banned by a U.N. treaty because of their persistence in the environment and health risks.
One step in the right direction would be to require the chemical business to make their products in the same place, since all forms of transport have their dangers. Another would be to impose regulations that forced the industry to find better ways of making PVC or otherwise managing the chlorine.
Chemical fires, leaks and explosions at plants or in transit should be a legacy of the 20th century; banished after the hard lesson of the deadly 1984 explosion in Bhopal, India. But today, there are other dangerous substances being transported on our rails and highways, such as ethylene oxide, used to make antifreeze and disinfectants. It’s one of the few things that can burn without having air present, and it’s explosive and toxic, Jones said.
If the derailment in Ohio had led to a BLEVE and people were killed, nobody would question doing whatever it takes to fix the problem at its root. It might mean forcing the chemical industry to change what it makes and how, but when such things become mandatory, innovative people find a way.
Faye Flam is a Bloomberg Opinion columnist covering science. She is host of the “Follow the Science” podcast.
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