A ROTTEN egg smell has made 22 people ill, stopped traffic and closed scores of businesses in the central Queensland city of Rockhampton.
Paramedics have treated 22 people for headaches, nausea and vomiting.
Three people were taken to Rockhampton Base Hospital.
Authorities are investigating, but the cause of the smell is still unknown.
Businesses on Glenmore Street between Dooley, Park and Robinson streets have been evacuated as a precaution.
Dave Finlay, from a four-wheel drive repair business on Glenmore Street, told AAP the smell began on Monday morning.
“It’s been on and off all day,” he said.
“Smells like rotten eggs … a barbecue gas smell.
“We’ve shut the doors and pulled the roller doors down.”
Mr Finlay said some staff had headaches.
“We’ve had to tell customers they can’t pick up their cars until tomorrow, the police have blocked the roads,” he said.
“Authorities are taking it quite seriously. They’ve stopped all the traffic.”
Mr Finlay said there had been a similar bad smell six weeks ago.