Retired secondary school teacher Howard Williams remembers watching “a gumtree literally explode from the heat”.
It was the beginning of the Hazelwood coalmine fire, which broke out on 9 February 2014 in the middle of a hot, dry summer.
Williams says he watched as the fire raced across the mine and towards an SEC administration building.
At the time, Williams was living in Morwell in Victoria’s LaTrobe Valley, separated from the mine by a fence and a freeway.
After helping his wife evacuate, Williams stayed behind, a decision he questioned in hindsight. “I was worried about the fire burning down the freeway reserve on our side,” he says. “Our property had a number of large trees and a lot of leaf litter which I was wetting down.”
About six days later, the fire roared on, with firefighters working to contain the huge blaze that had an almost unlimited supply of fuel.
Nearby, Williams had just finished a bit of shopping and was walking back to his car “as I always did”. By the time he got there, he was breathless. An emergency alert warned of high carbon monoxide levels.
The mine fire ultimately burned for 45 days, blanketing nearby Morwell and the surrounding area in smoke. For 27 of those days, levels of fine particle pollution – called PM2.5 – exceeded the national environment protection measure.
Williams, a community representative on the emergency management team, was concerned. Unlike the standards set for emergency workers, “the community could be exposed to higher levels of small particulates, higher levels of carbon monoxide and other dangerous gases,” he says.
A decade on, new research published in the journal Respirology finds Morwell residents showed signs of accelerated lung ageing four years after the fire.
Epidemiologist and former respiratory physician and emeritus professor at Monash University, Michael Abramson, co-wrote the paper. He was the principal investigator for the Hazelwood health study from its establishment in 2014 until the end of last year.
While the analysis did not show a causal link, Abramson says there is a statistically significant association between exposure to the fine particles in the smoke from the fire, equivalent to 4.7 years of lung ageing. “In other words, the lungs of these participants have aged more rapidly than they would have had they not been exposed to the smoke,” he says.
In late 2017, researchers conducted a clinical test called the “multiple breath nitrogen washout” on 313 Morwell residents who were exposed to pollution from the mine fire, and 166 people from Sale – a town 50 km east – in early 2018.
In the test, participants breathe in 100% oxygen, while specialised equipment measures the time it takes for nitrogen to wash out of the lungs over multiple breaths.
The method was chosen for its ability to identify more subtle signs of lung disease, Abramson says. It measures something called ‘ventilation heterogeneity’, an indication that parts of the lungs aren’t functioning well by measuring how gases mix.
In young people with healthy lungs, gases tend to mix evenly and efficiently, he says, compared with older people and those with lung disease.
Abramson says the results show an association between exposure to pollution from the mine fire and increased ventilation heterogeneity – less efficient mixing – about four years after the event, while controlling for other factors like age, sex, cigarette smoking and occupation.
The paper is an output of the respiratory stream of the Hazelwood health study, a series of investigations into the long-term effects of the fire on the community’s health.
Prof Brian Oliver at the University of Technology Sydney, researches lung diseases and environmental health including the consequences of exposure to air pollution. He says “any form of air pollution – and that includes both gases and particulates – is bad for lung health”.
It’s easy to see the short-term health effects for events such as fires, which are episodic and involve higher levels of exposure, Oliver says. “Because generally when you have a massive exposure, there’s a huge rush of people, unfortunately, going into hospitals with things like cardiac events or respiratory events”.
Longer term, the data is often less clear, although “we definitely know it is bad”.
Ten years on, Williams says many in the community continue to experience health, social and psychological effects from the Hazelwood mine fire.
“Being exposed to what people were in those 45 days could not have been beneficial,” he says. “The difficulty is, the people who are most severely impacted have passed away, and many of them passed away from lung conditions.”
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