by ALEC SMART
Garbage in a waste disposal truck suddenly ignited during a recent rubbish collection in the Eastern Suburbs, but thankfully the fire was extinguished by quick-thinking Waverley Council refuse workers. Disaster was averted when a crew member standing on the back of the truck alerted the driver after he saw an explosion and sparks as the compacter compressed the waste within.
The rubbish truck crew followed emergency procedure and stopped their vehicle at the nearest safe location then doused the flames with an onboard extinguisher.
The truck was then returned to the Waverley depot where the garbage compacter was thoroughly hosed down to ensure stray sparks didn’t reignite – which might otherwise have resulted in the whole truck catching fire and potentially exploding.
The incident, in the last week of January, was caused by lithium batteries, which are notorious for detonating under pressure, and, like conventional batteries, should never be included with household waste.
A Waverley Council spokesperson told City Hub “In the past 12 months, there have been five other incidents linked to batteries. It is unknown how many of these were lithium, but these are particularly dangerous because when a lithium battery is damaged, it can result in a spark that could ignite the highly reactive lithium and start a fire.
“Fires can also result when non-lithium batteries are damaged. These batteries may heat to the point where pressure builds inside, potentially producing an explosion. Battery fires can occur in waste collection trucks, as well as sorting facilities – basically anywhere where they are moved and there is a risk of damage to the integrity of the battery.”
Lithium-ion (Li-ion) batteries have become the world’s most popular form of rechargeable battery since taking over from conventional alkaline disposables and nickel-cadmium rechargeables, because they have double the energy output.
Li-ion batteries provide more power to electronic devices that demand high currents over long-term periods, such as mobile phones, electric vehicles and portable computers, and because no other batteries are yet capable of servicing this demand, Li-ion batteries are ubiquitous.
However, to generate that power, the battery relies on three main components: a positively charged cathode (metal oxide), a negatively charged anode (graphite), and a liquid electrolyte (a solvent containing lithium salts). These enable an electric charge to flow between the positive and negative poles at the respective ends of a battery.
Because of their reactive nature, the positive metal oxide and the negative graphite need to be separated, and this is typically achieved with a thin separator made of polyethylene plastic. But power surges, rough handling, mechanical abuse, battery overcharging, droppage and design and manufacturing flaws can cause weakening or breakage of the separator.
The separator can also melt through excessive heat build-up – such as when a laptop computer is placed on a bed or similar surface for long periods of operation, hindering the internal fan from efficiently cooling the circuitry.
Needless to say, when the separator is damaged and the two agents meet, it causes a short-circuit and begins what is technically known as a ‘thermal runaway’ and exothermic reactions are triggered, leading to a massive escalation in temperature, as high as 800 degrees celcius.
At that point the flammable electrolyte can ignite when exposed to the oxygen in the air, inevitably leading to fires and explosions. There have been numerous documented cases resulting in property damage and burn injuries, including electric cars and notebook computers spontaneously igniting, cargo planes crashing, and electronic gadgets catching fire.
Perhaps the most famous in recent history was the Sept 2016 massive recall of up to a million Samsung Galaxy Note 7 mobile phones in the USA after 92 reports of batteries significantly overheating, with 55 of those resulting in property damage when the phones burst into flames.
Li-ion batteries crushed within a garbage truck, where the pressure of the compactor reaches 16.2 megapascals (half of which would crush a nuclear submarine at depth), will force the unstable chemicals into reacting and that’s how the fire was ignited in the Waverley garbage truck.
Mayor of Waverley, Paula Masselos, said “This incident reminds us of the dangers of throwing batteries in the bin, whether it’s standard AAA or AA batteries we use in television remotes and children’s toys, to batteries found in other common appliances such as laptops, mobile phones, power tools and cameras.”
To reduce the fire hazard of Li-ion batteries the flammable liquid electrolyte needs to be replaced by a solid electrolyte, which is more stable. Lithium-sulfur (Li2S) is being tested and employed for some battery-powered products. However, because Li2S has a significantly shorter life-cycle – only around 20 recharges – than Li-ion, it won’t provide the much-needed substitute the world of consumer electronics demands.
United States Federal Aviation Administration (FAA) reported 206 air and airport Li-ion battery fire or explosion incidents between March 1991 and Jan 2018.
In Feb 2019, The US Dept of Transportation and FAA announced a ban on travellers storing mobile phones or batteries as cargo on passenger planes. Companies are also prevented from shipping batteries with more than 30 percent charge aboard cargo-only aircrafts.
Australia’s Civil Aviation Safety Authority (CASA) have issued recommendations for the carriage of Li-ion-powered portable electronic devices aboard aircraft, including the regulation: Spare batteries, regardless of their size, are not to be carried in checked luggage.
This came about after a potentially catastrophic incident in June 2014. A Fiji-bound Boeing 737 in Melbourne was hastily evacuated when one of 19 undeclared lithium batteries, packed into a passenger’s checked bag, short-circuited, igniting a fire in the aircraft’s cargo hold. A ground engineer alerted the captain after he spotted white smoke emanating from the aircraft just minutes prior to departure.
MH370 tragedy theory
A Li-ion battery explosion is one of the four primary theories attributed to the unsolved disappearance of Malaysian Airlines flight MH370. The Boeing 777 jet, with 227 passengers and 12 crew, vanished somewhere in the Indian Ocean on 8 March 2014 during a routine flight from Kuala Lumpur to Beijing, China.
The plane was carrying 221kg of Li-ion batteries divided between three pallets placed in the fore and aft cargo holds. Because the batteries were packaged in accordance with International Air Transport Association (IATA) guidelines, they were not regulated as dangerous goods.
Thirty-eight minutes after take-off, the captain bid goodnight to Malaysian air traffic controllers, then minutes later the flight suddenly deviated its course south-west instead of north-east, back towards Kuala Lumpur.
However, it flew over Malaysia and then changed direction and bore southwards for another seven hours in silence, detected only by satellite transmissions, before crashing into the Indian Ocean around 2000km west of Perth after running out of fuel.
There is speculation that everyone on board was simultaneously overcome with smoke and incapacitated with hypoxia, but not long afterwards, while still in Malaysian airspace, the captain or a crew member attempted to regain control, explaining how the aircraft’s course was suddenly manually altered to its southerly, albeit fateful route.
After a three-year search across 120,000 square kilometres of ocean failed to locate the aircraft, the inter-governmental agencies overseeing the operation suspended their activities in January 2017. A second search launched in January 2018 by a private contractor also ceased after six months.
Safe disposal of batteries
Batteries should never be put in recycling bins, as many contain toxic metals such as cadmium, mercury and lead. Li-ion batteries are more likely to be used in mobile phones, cameras, portable power tools and laptop computers.
There are numerous collection points across Sydney for the safe disposal of batteries.
Aldi supermarkets and most Officeworks stationery stores offer a free battery recycling service and will accept any brand of AA, AAA, C, D and 9V batteries, both rechargeable and non-rechargeable.
The NSW Environment Protection Agency Community Recycling Centre: https://www.epa.nsw.gov.au/
Or search online for a proper battery disposal facility at: https://recyclingnearyou.com.au/
Commercial businesses must have a commercial waste contract. For hazardous waste such as batteries visit: www.BusinessRecycling.com.au