Reactive Chemicals: The Stuff That Tries to Kill You After You Throw It Away

Reactive hazardous waste doesn’t become safely inert once you stop looking at it. Q&As include:

1. Don’t chemicals become safer as they age?
2. What exactly is “becoming dangerous?”
3. How do you know if an old solvent has turned explosive?
4. What other things might you own but shouldn’t touch?
5. What about finely powdered metal shavings from a metalworking process?
6. Is a discarded compressed gas cylinder similarly dangerous?
7. What about lecture bottles?
8. What else poses a danger?
9. What’s the upshot?

1. Don’t chemicals become safer as they age?

The “aging mellows everything” theory of chemistry is understandably popular among people who’ve never met an ether, a compound that improves with age the way a wasp nest improves with age.

Time does many things to chemicals. Mellowing is rarely one of them. In fact, for a large category of compounds, sitting quietly in a dark closet is precisely how they while away the hours becoming dangerous. You didn’t store a chemical. You incubated a problem.

2. What exactly is “becoming dangerous?” This sounds rather alarmist.

You have no idea. Let’s start with peroxide formers, since they’re the chemical equivalent of a landmine that assembles itself while you’re not looking.

Certain solvents react ever so slowly with atmospheric oxygen to form organic peroxides. E.g., diisopropyl ether, tetrahydrofuran, dioxane, and that old laboratory workhorse, diethyl ether.

This isn’t dramatic. There’s no hissing, no smoke, no ominous discoloration to alert the unwary. The peroxides simply accumulate, silently, invisibly, like a very patient assassin.

The trouble comes later, when someone opens the container, or evaporates the solvent to dryness, or worst of all, unscrews a crusty old cap that has partially crystallized peroxide caked around its threads.

Friction, heat, or a mechanical shock can then set off a detonation with no warning whatsoever. Laboratories have lost fingers, hands, and occasionally entire rooms to bottles that looked entirely unremarkable right up until the moment that they weren’t.

3. How do you know if an old solvent has turned into a bomb?

You generally don’t, which is the entire point of having this conversation.

Conventional wisdom dictates that if a peroxide-forming solvent has been open to air for more than six to twelve months, it should be treated with the same tenderness you’d extend to a sleeping rattlesnake. (N.B. The exact time window depends on what chemical you’re gambling with.)

Test kits exist. But the far more sensible option is to call people whose job it is to deal with this rather than shaking the bottle “to see.” (That would be us.)

4. What’s next on the list of things you might own but shouldn’t touch?

A name that considerably undersells the drama of its denotatum is “water reactives.” These are materials that regard water not as a solvent, but as an opponent.

• Elemental sodium and potassium are the most classic examples of water reactives. E.g., drop a chunk of either into a sink and you get a small, cheerful fire accompanied by hydrogen gas, which is itself flammable, which means you have now built your own miniature Hindenburg using nothing but tap water and poor judgment.
• Calcium carbide reacts with water to produce acetylene gas. Certain metal hydrides react with water to release hydrogen so vigorously that the reaction can ignite on its own.

And here’s a genuinely inconvenient truth: Water is what firefighters instinctively reach for, especially ad hoc pro tem ones. A water-reactive fire doused by a well-meaning bystander with a garden hose doesn’t go out. It gets worse, faster, and often with additional gas production.

5. What about finely powdered metal shavings from a metalworking process?

Funny you should ask.

Finely powdered metal shavings are called pyrophorics, which are substances that ignite spontaneously on contact with ordinary air. I.e., no spark required, no flame, no assistance from anyone beyond the original sin of exposing them to oxygen. Three examples:

• Finely divided metals like titanium, zirconium, aluminum, and others, behave very differently as fine powder than they do as the solid ingot version you’re picturing. E.g., a block of titanium is inert and boring. But titanium dust is a different creature entirely. Having vastly more surface area for oxygen to attack, it can combust the instant it’s disturbed.
• White phosphorus is similarly incorrigible, which is why it’s stored under water—the water being the only thing standing between it and the surrounding atmosphere with which it’s all-too-eager to react.
• Alkyl aluminum compounds that are used in some industrial processes are so reactive that they’ll ignite in open air on contact, which makes “leave it in an unlabeled drum in the corner” the kind of storage plan that’ll get scripted into a future OSHA training video.

6. Is a discarded compressed gas cylinder similarly dangerous?

A compressed gas cylinder is a container holding energy the way a loaded spring holds energy. Except the spring doesn’t occasionally contain something toxic, flammable, or both.

Consider that aging cylinder of a gas that nobody remembers ordering, the one tucked behind the loading dock since the last time anyone used a fax machine without irony.

Corrosion doesn’t announce itself politely. Many subtle insults can turn a stationary metal tube into an unguided missile powered by its own contents or release its payload into a room with people sitting in it. E.g., a valve that’s rusted through, a compromised seal, a cylinder that’s been dropped and never reported, etc.

7. What about lecture bottles? They’re so small. How can they be a problem?

For those of you just joining us, be it known that “lecture bottles” are small cylinders used for laboratory gas samples, cited herein as a good example of a peculiar menace because their diminutive size lulls people into treating them casually.

A five-pound cylinder of something like arsine or phosgene is not made friendlier by being small enough to fit in a desk drawer. If anything, it gets worse. Because desk drawers are rarely equipped with ventilation; nor are they commonly fabricated with the structural integrity requisite to blast mitigation. (IKEA, we’re lookin’ at you.)

8. What else is on this list of homicidal garbage?

A few more entries:

• Shock-sensitive and self-reactive compounds can detonate from the mechanical shock of simply being moved. E.g., picric acid that’s dried out and crystallized around a cap.
• Oxidizers encourage anything nearby to burn far more enthusiastically than it would otherwise. Although they don’t spontaneously combust all by their lonesome, oxidizers can transmogrify an otherwise manageable trash fire into a ready-for-TV conflagration.
• Self-heating materials like oily rags, certain organic materials, and/or some agricultural byproducts can undergo slow oxidation that generates heat faster than it dissipates, eventually reaching ignition temperature with no external spark to blame. I.e., spontaneous combustion.

9. What’s the upshot?

The honest truth is that reactive chemicals are often the price you pay for doing anything commercially or scientifically productive. E.g., synthesizing compounds, treating metal, maintaining electronics, running research.

But it’s crucial to remember that hazardous waste doesn’t become safer with neglect. And it never announces its transformation from “funny smelling” to “actively lethal.”

By way of review:

• Peroxide formers turn explosive on a schedule nobody’s watching.
• Water reactives treat waterborne rescue efforts as an insult.
• Pyrophorics require no ignition source beyond the air you’re already breathing.
• Compressed gases store potential energy behind aging metal and rubber.

Each is an excellent reason to know what you’re storing, how old it is, what it’s compatible with, and—most critically—when it’s time to have it properly characterized, packaged, and removed by people who do this for a living.

That would be us: careerists who find these challenges genuinely interesting rather than simply terrifying. From peroxide-prone solvents to pyrophoric powders, our specialists will identify, stabilize, and safely remove reactive chemical waste from your facility—in full compliance with federal, state, and local mandates.

The alternative is waiting for your chemical inventory to make the decision for you, on its own schedule, with considerably more drama than a phone call to us would ever involve!

Contact us today.