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Storing incompatible hazardous chemicals

Find out what you must consider when storing incompatible hazardous chemicals at your place of work.

When incompatible hazardous chemicals come into contact with each other, the chemicals can react to cause fire, an explosion or release toxic, flammable or corrosive vapours.

Workplaces that use, store or handle hazardous chemicals must have systems and procedures to prevent incompatible materials interacting under section 354 of the Work Health and Safety Regulation 2011 (WHS Regulation).

You must also consider incompatibilities when managing spills (refer to section 357 of the WHS Regulation).

Managing their storage

If you are a person conducting a business or undertaking (PCBU) who manages the storage of incompatible goods, you must:

  • identify each of the hazardous chemicals used, stored or handled at the workplace
  • recognise goods or other materials that are incompatible
  • put in place suitable measures to prevent the interaction of incompatible goods.

The segregation tool for dangerous goods can help you determine if combinations of hazardous chemicals are compatible or not.

You should review the storage and handling information provided in the safety data sheet (SDS) for each hazardous chemical when identifying incompatible goods.

After you review the SDS information you should list each incompatible hazardous chemical or other material mentioned and take appropriate measures to keep them apart.

Determining incompatible chemicals

The factors influencing compatibility are complex and you should consider the following list of issues:

  • Whether a violent reaction (fire or explosion) between one or more highly reactive chemicals may occur.
  • A reaction between two or more spilt goods may release flammable, toxic, or corrosive vapours or gases. Such reactions may occur rapidly or slowly over time until a build up of a hazardous material occurs, which can then cause an emergency situation.
  • Released or spilled goods may deteriorate, contaminate or destroy the packaging materials of another incompatible product to worsen a situation.
  • Flammable goods stored next to other toxic or corrosive materials may catch fire causing rapid dispersal of the toxic or corrosive materials into the environment.
  • Flammable materials may catch fire and cause flame impingement on products stored nearby (e.g. gas cylinders) resulting in rupturing of the gas cylinder.
  • Fire suppression media suitable for one type of hazardous chemical may be incompatible with another hazardous chemical stored in the same area.
  • How the materials used in the construction of spill catchment systems will react with hazardous chemicals spilt in the catchment (e.g. hydrochloric acid will rapidly corrode concrete walls used as a spill containment system unless a protective coating is used (e.g. chemical resistant epoxy resin).


Once you identify incompatible goods, you will need to determine the best approach to keep these apart. Control measures to keep these goods apart will depend on the hazardous properties and the level of risk presented from each scenario.

More information

More information on the storage of dangerous goods is available from the Australian standard AS3833: The storage and handling of mixed classes of dangerous goods in packages and intermediate bulk containers.