Outdoor workers could be at increased risk of heat-related illness, possibly even death, during this year's predicted hot and dry El Niño summer.
There are no government-enforced temperatures that force outdoor workers to down tools when it gets too hot experts believe there needs to be more regulation.
Death from occupational heat stress is rare but 17 Australians died from heat-related causes between 2000 and 2015.
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Iconic Metal Roofing owner Ivan Lazic said it gets "pretty hot up there" on people's roofs during Sydney's summers.
Lazic hasn't measured the temperature when he's working on a house on a hot day but a black roof can reach double the ambient temperature.
He said his team normally downed tools when temperatures hit about 38 degrees but he thinks there should be a standard stop-work temperature.
"Everyone has their own opinions. When everyone has their own opinion it gets tricky," he said.
"It would be good to get it a bit more regulated."
Lazic encourages his team to stay hydrated and speak up if they're struggling but he is at a financial loss if his team stops work due to the heat.
"The only thing is because you've got to pay the boys a certain amount each week, I feel like maybe the government needs to have a … subsidy or something like that where the boys can fill it out to say they have missed this many hours because of the heat."
Should Australia have a stop-work hot weather temperature?
Liz Hanna, a professor at the Institute for Climate, Energy and Disaster Solutions, said heat-related illnesses should be taken more seriously but creating a stop-work temperature was incredibly complex.
"It's not rocket science but it's a matter of really taking heat seriously because it's not worth people going to work and dying," Hanna said.
Australia's diverse climate makes it difficult to decide on a stop-work temperature due to differing humidity levels and other things like different environments and the physicality of the work.
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Hanna believed a temperature limit would need to be made by workers and employers because if it was government-mandated, compliance could be an issue.
"Australia needs to address heat right from the very, very top in a structural thing in terms of building law and contract law all the way through to the employers and all the way through to the attitude sort of the workers themselves," she said.
"It's really important that we get sensible about it (heat-related illness) so that we are not forced into shutting down industries and shutting down work all through summer because the nation can't afford it.
"We need to be very aware of the fact that this is a big motivator for people to work, to either force people to work beyond what to safe for them or to push themselves."
Hanna suggested builders should include a heat delay clause in contracts, like a rain delay clause, to take the pressure off tradespeople pushing through extreme heat to make a deadline.
"If a house is supposed to be finished and it rains a lot then you can't go and sue the builder – we need that for heat," she said.
Powerful union the CFMEU has included stop-work temperatures in some of its enterprise bargaining agreements but they differed in each state and territory.
The stop-work temperature in Victoria and ACT was 35 degrees while in Queensland it was 35 degrees or 29 degrees with at least 75 per cent humidity.
In South Australia, it is 37 degrees.
CFMEU National Secretary Zach Smith said its enterprise agreements included extreme weather provisions to protect workers from potentially deadly heat on construction sites.
"We're staring down the barrel of a long and hot summer," Smith said.
"Extreme and dangerous weather will put workers' lives at risk on construction sites unless the rules our union has won in agreements are followed."
Smith said climate change would mean more unsafe heat on Australian worksites.
"Australia needs to dramatically reduce its carbon emissions if we want to have a strong and safe construction industry into the future," he said.
"We need to address climate change as a workplace safety issue."
Western Australia acting WorkSafe Commissioner Sally North said there was no temperature cut-off in workplace legislation because there were "many variables to consider besides the actual temperature".
"This includes the amount of air circulation, the level of humidity and the sensitivity and acclimatisation of the workers," North said.
What can be done to prevent workplace heat-related illness?
Hanna said her research into how outdoor workers managed hot weather showed most people overestimated their ability to work "by a large margin".
"Many of these people think they can go on, and very much surprised in the fact that they start feeling wonky, and start showing symptoms at a much lower temperature than they think they can," she said.
She noted there were many professions that involve outdoor work – not just people on construction sites.
Hanna said more people died in Melbourne due to heat-related illness compared to Adelaide and Perth because their temperatures tended to be more inconsistent, giving people less of a chance to acclimatise.
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She said workers needed to listen to their bodies and look out for each other.
North said heat stress could be avoided by precautions like drinking cool water, having "reset pauses in a cool place" and helping sweat evaporate through increased circulation.
"Workplace safety laws require employers to ensure that workers are not exposed to hazards and this includes, as far as practicable, protecting employees from extremes in temperature," she said.
Some of the precautions include hydration testing of workers, increasing lengths of breaks, avoiding peak temperatures where possible, ensuring workers are acclimatised and ensuring risks are identified.
"Workers are encouraged to raise health and safety issues – such as heat – with their employer, especially if they have concerns that the risks have not been adequately assessed or controlled," North said.
More information on working safely in the heat can be found here.
