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Researchers are surrounded by dangerous elements, from infectious microbes to cranky advisors. With hazards all around, it’s easy to forget how deadly even common lab chemicals are.

But don’t worry—we’ve compiled a list (ordered alphabetically) of common, dangerous chemicals to help you out.

What You Need to Know About Some Dangerous Chemicals in the Lab

1. Acetonitrile

Be careful with this flammable irritant. Once this solvent is inhaled, ingested, or absorbed through the skin, it converts to cyanide!

2. Chloroform

This volatile solvent can irritate the skin, eyes, and lungs. It also acts as an anesthetic that depresses the central nervous system. Once inside the body, it converts to highly toxic phosgene, a chemical weapon used during World War I.

3. Dimethyl Sulfoxide (DMSO)

DMSO is such an excellent solvent that it crosses healthy, intact skin—and takes whatever is dissolved along with it! Be sure to wear your butyl rubber gloves if you are dissolving large amounts of something toxic (such as the neurotoxic pesticide rotenone) in DMSO.

4. Formaldehyde

This common fixative is a suspected human carcinogen. Take advantage of the fume hood, because formaldehyde can cause dermatitis, sinusitis, and asthma! And don’t buffer formaldehyde with hydrochloric acid, because together they form a potent carcinogen, bis-chloromethyl ether.

5. 2-Mercaptoethanol (\beta-Mercaptoethanol, BME)

As if the smell of rotten fish wasn’t bad enough, 2-mercaptoethanol is a combustible corrosive. It can harm the skin and the mucous membranes, and cause larynx spasms, pneumonitis, and pulmonary edema when inhaled.

6. Methanol

Like other volatile solvents, methanol can easily enter the body through the lungs, gut, or skin. Once inside, methanol transforms to formic acid, which causes metabolic acidosis and blinding retinal toxicity.

7. Sodium Azide

This popular preservative is an extremely toxic skin irritant that can cause headaches, dangerously low blood pressure, and even heart failure. [1] Sadly, its toxicity and ready availability in labs have made it a method of suicide for researchers. [2] Another word of caution: don’t pour sodium azide down the sink where it can react with copper and lead pipes, forming highly explosive substances!

8. Sodium Hydroxide

Disturbingly, it’s better to be splashed in the eye with concentrated acid than sodium hydroxide. Acids precipitate proteins, which form a protective “scab” over unharmed tissue, but strong bases like sodium hydroxide saponify fatty acids and destroy cell membranes. The “scab” never forms, so the base can just keep burning its way through. Wear your goggles!

9. Sodium Hypochlorite

In solution, this becomes bleach—an excellent anti-microbial because it is a strong and corrosive oxidant. While most researchers have gotten a burning whiff (and maybe a splash) of this irritant, they may not know that bleach can actually cause allergic contact dermatitis. Future exposure can then trigger skin reactions to even dilute bleach.

10. Tetrahydrofuran (THF)

THF is a flammable solvent. Over time, THF produces shock-sensitive, explosive peroxides. If the THF evaporates off, the peroxides will concentrate in the remaining solution. Even slight bumping of a container containing concentrated peroxides can result in an explosion.

It’s worth noting that hydrofluoric acid vapors are also an inhalation hazard and can cause eye and throat irritation.

Hopefully, this list reminded you to treat even everyday chemicals with a little caution. Read our follow-up post on even more bad chemicals in the lab!

Are you paranoid about poisoning yourself and your lab buddies, or just want an easy summary of safety data sheets? Download our free hazard diamond poster and pin it up in your lab.


  1. Chang S, Lamm SH. Human health effects of sodium azide exposure: a literature review and analysis. Int J Toxicol. 2003;22:175-186
  2. Le Blanc-Louvry I, Laburthe-Tolra P, Massol V, Papin F, Goullé JP, Lachatre G et al. Suicidal sodium azide intoxication: An analytical challenge based on a rare case. Forensic Science International 2012;221: e17–e20

Further Reading

Originally published April 2013. Reviewed and updated October 2021.

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