Information Sheet: Focus on compliance - Fire risk from transparent bottles containing clear liquids stored in direct sunlight


WorkSafe Mines Safety has noted an increase in the number of incident notifications involving fires caused by transparent bottles containing clear liquids refracting and magnifying sunlight, with 29 incidents reported since July 2020.

The majority of reported incidents involved transparent plastic bottles filled with water being stored in direct sunlight, although other liquids also caused fires. In many instances, refracted sunlight ignited the packing cardboard and wooden pallets used to transport or store the bottles. The resulting fires caused damage to mobile plant, sea containers and other assets, and posed a risk to workers.

With the onset of summer and higher temperatures across Western Australia, it is anticipated that these types of incidents have the potential to increase if not addressed.

Contributory factors

By storing transparent bottles that contain a clear liquid in direct sunlight, or even leaving one in a car, the bottle can act as a lens, focusing sunlight into a high energy beam that is intense enough to cause adjacent material to smoulder and catch fire. A similar effect can also occur from highly reflective surfaces or glass.


Under the Work Health and Safety Act 2020 and the Work Health and Safety (Mines) Regulations 2022, there is a duty to notify or report certain incidents to the regulator.

Notifiable incidents [ss. 35-38 WHS Act] include:

  • an uncontrolled implosion, explosion or fire.

Reportable incidents [r. 5 WHS Mines Regulations] include:

  • an incident that results in illness or injury that requires medical treatment
  • damage to any plant, building or structure so as to impede its safe operations.

Actions required

  • Designate an undercover or shaded area for unloading transparent bottles containing clear liquid.
  • Store transparent bottles containing clear liquid in an undercover, enclosed or shaded area where sunlight cannot shine through the bottles.
  • Cover transparent bottles containing clear liquid fully with heavy-duty, non-reflective tarpaulins, if exposed to direct sunlight, and store away from combustible material.
Last updated 20 Dec 2022

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