Top 3 Safety Tips for Teachers When Storing Chemicals in School Science Labs

Top 3 Safety Tips for Teachers When Storing Chemicals in School Science Labs


Typically, science teachers and other school personnel such as maintenance workers receive regular training on hazardous chemicals
and wastes. Nevertheless, we often find incompatible chemicals stored together, sometimes due to chemicals being stored alphabetically rather than by compatibility, and sometimes inadvertently. Sometimes, “household” hazardous chemicals such as ammonia and bleach are thought to be rather innocuous, since they are sold over the counter and most of us have them in our homes. Even scientifically-trained workers can forget the inherent dangers of chemicals and become complacent with these “everyday” substances.


Bleach and ammonia are two of these common products, which people use for cleaning and often store together under kitchen and bathroom sinks, in a bin in a laundry room, or out in a garage. Bleach and ammonia, however, react together to form toxic chloramine vapors, which have the potential to form hydrazine, an explosive chemical. In addition to respiratory irritation, hydrazine can also cause edema, headache, nausea, and seizures.  Teachers and other school employees must recognize which chemicals should not be stored together.


Because bleach and ammonia have high pH values, over-the-counter bleach or sodium hypochlorite solutions are often stored in base cabinets with ammonia and ammonium hydroxide. Science teachers who know that bleach cannot be stored with ammonia have tried to solve this issue by storing bleach in their acid cabinets. There is just one problem…bleach reacts with acids to generate another deadly compound, chlorine gas. This can happen with plain old vinegar (acetic acid), an over-the-counter acid. If this reaction occurs in an un-ventilated or poorly-ventilated area, an employee could quickly be overwhelmed by chlorine gas and lose consciousness or even die (chlorine gas has been used as a chemical weapon).


Chemical incompatibility relates to spill cleanup as well. Generally, when corrosives are spilled, one would neutralize
the corrosive to make it safe for cleaning up. Often, vinegar is used for base spills and baking soda is used for acid spills. However, as mentioned before, using vinegar to neutralize bleach would liberate chlorine gas. Therefore, never neutralize bleach or sodium hypochlorite spills.

In conclusion, keep your colleagues, your students, your family, and yourself safe. Do not store chemicals alphabetically, store bleach
by itself, and never mix cleaning agents.  – Shanah Kirkwood, Senior Environmental Specialist, Aurora Environmental Services, Inc.