Background
On 11 January 2021, the department received a report of an incident at a mine site where an electronic cigarette (vape) battery spontaneously ignited in a worker's pocket while he was travelling in a utility with two other workers. The statements received with the report describe the combustion event not unlike fireworks going off and flying around the inside of the vehicle the workers were travelling in. The worker received severe burns to his leg.
Summary of hazard
The cause of the explosion is known as "thermal runaway". The runaway refers to the very rapid discharge of the battery which occurs when the battery overheats to dangerously high temperatures, resulting in inner fire and explosion, and chemical and thermal burns to the user.
Contributory factors
The Health NSW fact sheet, Are electronic cigarettes and e-liquids safe? states that "the products available in Australia use a wide variety of parts and are sourced from many different manufacturers, including overseas manufactures where safety and quality controls are unknown." This includes the quality and safety of the lithium-ion batteries used in e-cigarettes.
In their submission to the Australian Parliament Inquiry into the use of Marketing of Electronic Cigarettes and Personal Vaporisers in Australia, the Australian Competition and Consumer Commission (ACCC) stated it was concerned about the potential safety risks from e-cigarette batteries:
E-cigarettes contain interchangeable parts, often including extra-low voltage lithium batteries. Failure of these parts has been linked to ignition of E-cigarettes, with a number of incidences of burns injuries reported overseas. Many have been linked to overcharging and overheating of batteries, causing the device to ignite or explode in close proximity to the user.