The variety of chemicals commonly present in the laboratory poses the potential for accidental hazardous chemical reactions or explosions. A hazardous reaction occurs when two or more chemicals that are incompatible combine, resulting in an undesirable or uncontrolled reaction with adverse consequences. Such reactions may result when incompatible chemicals spill by accident, inadvertently mix as chemical waste, or combine unwittingly during experimental procedures.

Hazardous reactions may cause any one or more of the following:

  • dispersal of toxic dusts, mists, particles
  • explosion
  • fire
  • formation of flammable gases
  • formation of shock or friction sensitive compounds
  • formation of substances of greater toxicity
  • formation of toxic vapors
  • heat generation
  • pressurization in closed vessels
  • solubilization of toxic substances
  • violent polymerization
  • volatilization of toxic or flammable substances

It is easy to become complacent with chemicals used everyday in routine procedures. It is prudent to check for incompatibility whenever making a change in chemical procedures. Chemical incompatibility is the primary reason you do not store chemicals on the shelf alphabetically. If there is an accident, adverse reactions may make the situation worse.

Safety Data Sheets will list reactivity information in Section 10: Stability and Reactivity Data within the form. References of incompatible chemical combinations include:

  • Handbook of Reactive Chemical Hazards; L. Bretherick, 6th edition 1999
  • Manual of Hazardous Chemical Reactions, National Fire Protection Association Manual 491M