CHEMICAL LABORATORY SAFETY OXIDATION HAZARDS: MORE THAN JUST AIR

Objectives

Oxidation Hazards: More than Just Air: American Chemical Society chemical safety video courses

Important Concepts

• The components of the fire triangle are fuel, an ignition source, and an oxidizer.

• There are many oxidizers besides oxygen.

• Always read the MSDS for any chemical you use in the laboratory.  Note particularly the recommended procedures for cleaning up spills and storing the chemical.

• The three rules of storage for oxidizers are:
  • don't store oxidizers (or any chemicals) if you don't need them;
  • if you must store them, keep as little on hand as possible
  • store oxidizers and flammables separately.

• Store incompatible chemicals separately.   Many oxidizers, such as hydrogen peroxide and nitric acid, can react explosively with other oxidizers.   Non-oxidizers, such as acetic acid, can also react explosively with oxidizers.

• The evaporation of liquid oxygen can raise the oxygen content in the laboratory space enough to reduce the flashpoint of combustible materials.

• Perform all work with perchloric acid in a dedicated fume hood equipped with a washdown system, a scrubber, and a self-contained exhaust system.

• Many chemicals autooxidize to form shock-sensitive peroxides.   Examples are ethers, alkali metals, metal azides, ketones, and vinyl halides, but there are many others.

• Always date containers of peroxidizable chemicals when you first open them, and test for peroxides regularly.  DO NOT OPEN bottles of peroxidizable chemicals with illegible labels or those older than the disposal date specified by the manufacturer or your laboratory's operating procedures.    Dispose of them as hazardous waste according to your organization's waste disposal procedures.