Dangerous Chemicals in School Laboratories

Lehane Environmental recently attended a Secondary School to carry out a controlled clean out of the school laboratory.  During the course of these works a quantity of 2,4-Dinitrophenylhydrazine was identified which had dried out.  2,4-Dinitrophenylhydrazine can deteriorate over time to a shock-sensitive explosive. Take exceptional care if there is evidence of drying out, crystallization or contamination. It may be very dangerous to attempt to open the container.  In this instance, the chemical had dried out and so we recommended that the Secondary School contact the Army Bomb Disposal Team.  The Defence Forces deployed the Explosive Ordnance Disposal (EOD) Team to make safe the unstable chemical.  The chemical was removed to a safe location where it was made safe through the use of a controlled explosion.

This incident and many more throughout the country have highlighted the importance of regular inspections of School Laboratories and Chemical Stores.  If you are in any doubt about the dangers of chemicals in your laboratory, please contact Lehane Environmental and speak with one of our in-house DGSAs (Dangerous Goods Safety Advisers) for advice – 1850 730 730


Inspection of Chemical Storage Areas

  • Conduct a regular cleaning and tidying of laboratories, stores, fume cupboards, cupboards, containers and shelving.
  • Check the segregation of chemicals, the condition of containers and labelling regularly.
  • Carry out an annual check on the chemicals with limited shelf life and arrange for disposal as appropriate.
  • Do not allow an excessive amount of waste to accumulate before disposal.
  • Stock take and place orders annually. Never repeat the previous year’s order without checking that there is less than one year’s supply of each material on the list.
  • Ensure that fire appliances are in working order and that first aid and appropriate personal protective equipment are available at all times.


Chemicals with short shelf lives
Some chemicals may have short shelf lives, deteriorate in storage and eventually offer increased risks to health and safety. Other chemicals may deteriorate harmlessly with a change in composition. Many chemicals, e.g. aluminium oxide, have extremely long shelf lives. Chemicals can fall into these categories for a number of reasons:


Deterioration of stock

Some chemicals deteriorate and thereby become less effective. Some may thereby also offer increased risk, others may not. Some chemicals in this category may deteriorate by decomposition, causing increased pressure in their container e.g. hydrogen peroxide. If there is doubt about their condition they should be opened in a fume cupboard. Other chemicals change harmlessly over time to form new compounds. Their continued use may produce confusing results or they may simply become less effective. Examples are iron(II) salts, which become partially oxidised to iron(III), and lithium chloride which is deliquescent and often becomes a saturated solution.


Risk of oxidation

Some chemicals may explode on oxidation in certain circumstances e.g.2,4-dinitrophenylhydrazine which has dried out or potassium metal which is old stock, discoloured or has been stored incompletely covered by oil, may explode in certain circumstances.


Risk of peroxide formation and detonation

E.g. ethoxyethane (diethylether) and propan-2-ol may form peroxides on exposure to light and air. These substances should be stored in the dark, not allowed to evaporate to dryness and not kept for more than two years.


Risk of contamination

Chemicals should not be returned to the stock container where there is any risk of contamination. Mixtures of oxidising agents, e.g. potassium manganate(VII), with dust, paper or organics may ignite or detonate if exposed to friction.

Please review attached document for further useful information.