The Monsters Slowly Growing in Your Chemical Storeroom

During a routine chemical inventory inspection at a rural school, the Laboratory Safety Institute encountered a bottle of nitric acid — generally, nothing that rings the alarm bells, especially since the bottle was in a secondary containment box inside an acid cabinet. However, when we noticed crystals had formed inside the bottle, and three bottles of ammonia nearby, along with a bottle of ammonium hydroxide that was clearly compromised, we backed away slowly and called the bomb squad.

Crystallized nitric acid bottle—note white deposits on the exterior shoulder and evidence of internal crystallization (cap seal likely compromised).

Ammonium hydroxide stored on shelf near the acid cabinet—an incompatible arrangement that promotes ammonium nitrate formation.

Later, we learned that the doors to the acid cabinet had been left open for months because staff members smelled fumes and wanted to let the cabinet “air out.”

We quickly realized that this setup could allow vapors to mingle and lead to the formation of ammonium nitrate—a terrorist favorite that has been responsible for the largest non-nuclear explosions in modern history. Although the hazmat team concluded the material was not energetic at the moment and could remain onsite for controlled disposal, this experience highlights some real-world issues with chemical storerooms at campuses and industrial labs across the country.

As this post was being prepared, another incident involving “sleeping” storeroom monsters hit the news. Staff at Shaw University in Raleigh, North Carolina, discovered a container of crystallized diethyl ether — another unforgiving substance that has resulted in life-threatening burns, amputations, and even death. The police, working with fire and federal agencies, secured the site and conducted a controlled disposal.

How monsters are born

As chemicals sit quietly on the shelf, vapors can migrate, moisture can enter, and incompatibles sitting nearby can react to form salts, peroxides, or other unstable products. Over time, what’s on the shelf may not look anything like what you bought. A clear liquid may grow white crystals, or a dry white powder may turn into a sticky brown mess.

It’s important to know what the substances in storage are supposed to look like in the first place, and to conduct regular, well-documented inspections. Below we’ve pulled together practical advice (and hard “do nots”) based on real incidents so you can spot the problem early, before the little chemical monsters mature, reproduce, and start forming militias.

First rule: follow the storage instructions — no exceptions

Read the label and the Safety Data Sheet (SDS). Section 9 of the SDS tells you the normal physical state and properties (e.g., “clear liquid,” “white crystalline solid”). If your material doesn’t match that description, treat it as suspect.

Do:

• Store per the SDS (temperature, light sensitivity, dryness, segregation).
• Segregate families: oxidizing acids (nitric acid) away from ammonia/ammonium sources, organics, and flammables. Acids and bases stored separately.
• Put oxidizers and corrosives in corrosion-resistant cabinets, with secondary containment (trays rated for the chemical).
• Keep light-sensitive chemicals in dark or amber bottles and out of sunlight.
• Use cool storage when required (refrigerators must be rated for flammables if needed).
• K–12 schools should order pre-diluted acids where practical.

Don’t:

• Leave chemical cabinet doors propped open for “venting.” That defeats segregation and containment.
• Store nitric acid next to ammonium hydroxide, ammonia bottles, or organics.
• Rely on brittle or stained plastic secondary containment — replace it.
• Try to “fix” a compromised bottle (re-sealing, wiping crystals off, transferring) unless you are trained and authorized.

Recognize the warning signs (inspect regularly)

A quick inspection program saves lives.

Red flags to watch for:

• Crystals inside bottles or white deposits on shoulders (may indicate salts, e.g., ammonium nitrate from nitric acid reacting with ammonia).
• Change of physical state: a powder that is now clumped/sludgy; a liquid that’s become cloudy, viscous, or solidified.
• Color change: clear to yellow/brown; white to brown.
• Corroded lids, swollen caps, staining around cap threads.
• Expired materials or long-undated bottles with no date received/opened.
• Strong or unusual odors coming from a closed cabinet.
• Containers with pressure bulge or unusual sounds.

If you find a changed or “crystallized” container — immediate steps

(These steps are strict. Do not improvise.)

1. STOP. Do not touch, move, open, or try to clean the container.
2. Isolate. Clear the area and restrict access. Control ignition sources and vibrations.
3. Document from a safe distance. Take photos and note adjacent chemicals (especially ammonia, organics, flammables).
4. Label the area. Mark shelf/cabinet and record date/time of discovery.
5. Call professionals. Contact your campus EHS, local HazMat, or fire department. For suspected oxidizer/ammonium nitrate formation or peroxide-containing ethers, involve HazMat/EOD or contracted hazardous-waste professionals — do not attempt disposal yourself.
6. Plan disposal. Let qualified responders or licensed hazardous-waste vendors handle removal once responders have cleared it.

For labs with capability vs. without

• R&D/industrial labs with trained chemists and analytics may have the instruments and expertise to safely analyze and even re-qualify certain reagents.
• Schools, small labs, and most teaching labs almost never have what’s required. If a chemical’s appearance has changed from the SDS description, dispose of it via proper hazardous-waste channels. Don’t take chances.

Why routine housekeeping matters

Money saved by “keeping things on the shelf” is a false economy when the alternative is an emergency response, evacuation, or a catastrophic incident. The best outcomes come from knowing what you have, storing it properly, inspecting it often, and disposing of the “mystery jars” promptly and professionally.

Quick TL;DR — the 5 rules to live by

1. Know what it should look like. Check SDS Section 9. If it’s different — stop.
2. Segregate and contain. Acids, bases, oxidizers, flammables, and peroxidables each need their own space and secondary containment.
3. Inspect often. Date bottles, do visual checks (weekly/monthly), photograph and record problems.
4. If in doubt, call experts. Don’t move or open suspect containers; contact EHS/HazMat or a licensed disposal vendor.
5. Get rid of old junk. Proactively remove expired or rarely used chemicals — cheaper and safer long term.