A 44-year-old man who was working in an anime store in Toowoomba's CBD last night has died of carbon monoxide poisoning.
Paramedics were called to the incident at 6.25pm after the man collapsed.
He was transported to hospital in a critical condition but later died.
The two police officers who first arrived at the scene were hospitalised as a precaution.
"Police arrived just prior to Queensland Ambulance Service (QAS), [went] inside and identified a generator running in the background," QAS senior operations supervisor Stephen Johns said.
It is believed the man was using a generator in a confined space while repairing storm-damaged floors.
Investigation underway
The incident will be investigated by the Department of Workplace Health and Safety, which says it cannot comment at this time.
Queensland Fire and Ambulance Services said the building was later identified to have high levels of carbon monoxide.
Mr Johns said emergency personnel wore breathing apparatus as they worked through the night to secure the area.
Street blocked off
Margaret Street was blocked off for hours and shoppers and employees at surrounding businesses were locked down until the fumes dissipated.
"I was just at the chemist getting a late-night script and wasn't able to get out to my car," Charleigh Brown told the ABC last night.
Alicia Freeman, who works in a hair salon beside the anime store, said authorities gave neighbouring businesses the all-clear to return this morning.
"The police were here all night going through and making sure it was all safe for us to come back in," she said.
"It's pretty traumatic and really sad.