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Safety Blog

Harboring Hazardous Chemicals and Disposing of Them

By Kenneth Roy

Posted on 2020-05-02

1. Harboring Hazardous Chemicals

Middle and high school science labs and chemical storerooms have been known to harbor large amounts of hazardous chemicals for years. Given the unknowns about school budgets, teachers try to purchase as many chemicals as they can afford in a given year. This in part is because the next year’s budget may or may not meet their needs with budget cuts and budget freezes. In this way, some chemicals are stockpiled, almost never used and at times, forgotten. This might be especially the case during the current pandemic with hazardous chemicals not being used during 3 to 4 months of school closings. This could even potentially be extended into next fall in some locations.

In this way, when purchasing chemicals, consideration needs to be given to the hazardous chemical nature vs its educational utility. For example, when considering peroxide forming chemicals like diethyl ether, will they be stored or infrequently used carrying them well beyond their required disposal date once open and exposed to air. Are there safer alternatives to this potential time bomb in the chemical store room or lab cabinet?

2. The Hazardous Chemical Inventory

Conducting a chemical inventory assessment is critical to making sure all chemicals are accounted for and making sure the expired ones are disposed of timely and appropriately. There can always be many surprises in this process such as:
• chemicals you never thought you had
• chemicals in damaged containers
• chemicals in poorly labeled containers
• chemicals in containers without labels
• hazardous chemicals/ unstable chemicals
• chemicals that are toxic
• chemicals in need of special handling
• chemicals that are never used
• chemicals that are seldom used
• chemicals in excessive quantities
• chemicals in large containers*
(*NSTA Safety Advisory Board safety paper –“Managing Your Inventory Part 1” –
Finally, is the chemical inventory process on going and accurate?

3. A Chemical Purchasing Procedure

Science teachers need to first have an established chemical purchasing procedure which addresses the criteria upon which chemicals should be selected for purchase. The NSTA Safety Portal has a safety paper which in part addresses this issue. The paper titled – “Managing Your Chemical Inventory – Part 2” ( states the following relative to chemical selection under the “Processing Chemical Requests” section:
“1. Chemicals on the “Acceptable Chemical List” are the only chemicals that can
be purchased. (All school districts should develop an “Acceptable Chemical
List”). One resource for this are the better professional practices noted in Rehab the Lab –

4. Resources for Selection of Chemical Disposal Candidates

The following are several resources to help teacher decide on which chemicals are definitive disposal candidates:

a. “Chemical Management Resource Guide for School Administrators” by EPA” – This is a useful resource for managing hazardous chemicals in science labs and other locations in the school facility. It will help determine which chemicals are disposal candidates and also what not to purchase!

b. “School Chemistry Laboratory Safety Guide” by Centers for Disease Control and Prevention and, National Institute for Occupational Safety and Health. Appendix C. “Substances With Greater Hazardous Nature Than Educational Utility”

This is a great resource and as the title notes – hazardous nature vs educational utility. For example – it shows the following at the beginning of this list:
Chemical CAS Number Hazard
Bromine 7726–95–6 – Oxidizer, corrosive, may be fatal if inhaled or ingested
Cadmium and cadmium compounds -N/A Known human carcinogen
Chromic acid 7738–94–5 Oxidizer, known human Carcinogen

c. Rehab the Lab – This site includes information on hazardous chemicals which should be banned in elementary, middle and high schools and also disposal methods ( It also has a section on least-toxic chemistry lab (

d. Safety Data Sheets (SDSs) – All hazardous chemicals have SDSs with information about hazards, storage, and disposal.

5. In the End

As the CDC and NIOSH publication state – your chemical inventory for hazardous chemicals comes down to the “greater hazardous nature vs educational utility!” Before ordering chemicals, know their hazards and can an alternative be found which is safer and worthy of educational utility! These decisions will make it safer for all and cost less for chemical disposal activities!

Submit questions regarding safety to Ken Roy at or leave him a comment below.

Follow Ken Roy on Twitter: @drroysafersci.



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