A MAN who was working on a Mooroobool roof when a chemical reaction caused a large explosion is being treated in hospital.
He and a second male were believed to have been cleaning the roof of the Olfersia Ct property when the blast occurred just after 9am on Monday.
Neighbours reported hearing a large explosion followed by several smaller explosions.
Resident Monica Stapleton who lives across the road from the house said she saw the men on the roof stripping off their overalls and hosing themselves with water.
"They were coughing and spluttering and didn't seem to be able to breath properly," she said.
The men left and are understood to have driven themselves to Cairns Hospital.
One is being treated and is in a stable condition.
Ms Stapleton said the explosion sounded "like a bomb going off" and she had to shut her windows as the smell of chlorine drifted past.
Another resident who lives on a nearby street said their home shook from the blast.
"It was bloody loud, it shook the whole house, then I heard five smaller bangs," she said.
Firefighter and Cairns station officer Guy Bulmer said the men had been contractors working on the roof, cleaning the tiles.
"There's been an explosion occur on the roof through the mixing of chemicals and they've suffered some degree of injury and they've self-mobilised to hospital," he said.
The roof is understood to have suffered damage to tiles, solar panels and a satellite dish.
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