Seven children and two adults suffered carbon monoxide poisoning in a video-game trailer that had been rented for one of the children's birthday party.

After playing video games in a 20-foot-long gaming trailer, one child reported feeling sick and suffering from a headache. Some parents thought it was heat exhaustion, but one by one, other children began falling ill.

Some of the victims were barely able to walk.

When firefighters arrived, they quickly determined the victims were suffering from carbon monoxide poisoning.

“Carbon monoxide is orderless, colorless and tasteless, so there's no evidence of it,” said Coweta County Fire Shift Commander Craig Shaerre. “The goal is to get all the oxygen you can to get rid of the all carbon monoxide that you can possibly get rid of.”

Firefighters said a carbon monoxide alarm was chirping when they arrived. Some witnesses credit an employee for realizing there was a problem and getting the children out safely.

GameTruck Atlanta tells 11Alive the company is replacing all of its carbon monoxide trailers in all of its trucks.

The mother who planned the party spoke to 11Alive by phone.

“We were in shock,” she said. “We have never experienced anything like this, and it’s last thing that I thought would have occurred.”

Georgia poison control officials said there are more than 320 cases of carbon monoxide poisoning reported each year, and 30 percent of those involve children.

All of the victims are out of the hospital and recovering at home.