TEN people have been affected by carbon monoxide poisoning at a Wodonga business, including a paramedic who was sent to help a patient.
Emergency service workers were called to the Wodonga Ice Skating Rink.
A call had been made after a person fell ill due to possible gas exposure at the venue.
CFA regional duty officer Rod Railton said one person was treated at the scene, but up to 10 people had been affected and later took themselves to hospital on Sunday.
"They had nausea and headache symptoms, which is normal for carbon monoxide poisoning," he said.
"We conducted atmospheric monitoring which found high levels of carbon monoxide.
The incident was caused by an ice smoothing machine.
Firefighters required breathing apparatuses and stayed on scene for four hours.
"I believe there was one ambulance officer who had slight side effects from poisoning," he said.
The skating rink returned to normal operation on Monday.
Mr Railton said none of those affected by the gas had been seriously injured.
"There was only one person at the skate rink who was unwell, the others went home and presented at hospital later in the day," he said.
"These incidents aren't very common at all.
"Because the ice skating rink is so well contained to keep the cold in, we had issues ventilating the building.
"We had to use fans to blow fresh air into the building and remove the carbon monoxide from the atmosphere."
Firefighters were also monitored for signs of exposure, but were not affected.
Carbon monoxide is colourless and odourless.
It can be fatal when it reaches high levels, with symptoms of poisoning including dizziness, vomiting, shortness of breath and blurred vision.
Owner Ken Jensen said the Queen Street business had continued to operate yesterday.
"It was just a precautionary thing to make sure no-one was jeopardised in any way," he said.
"It's all under investigation.
"They've given us the green light to go ahead.
"It's nothing major."
Mr Jensen said the incident was similar to having a faulty gas heater inside a home.
But he said "it's certainly not life-threatening" and noted the business continued to trade as normal.