A non-lethal gas grenade sent several people in Harlan County to the hospital Monday night.
It happened on East Main Street in Lynch, Kentucky. At first, police thought it was a meth lab explosion, but then determined it was a hand grenade.
11 people were inside the house at the time. Police estimate nine of those were children, and two adults. One child had to be flown to the hospital for treatment.
Police say some children were playing with an explosive tear gas grenade that dates back to the Vietnam War era.
Someone pulled the pin, and the device exploded, sending a CS gas throughout the house.
"It causes irritation to the throat, difficulty in breathing, skin irritation, eyes, causes mucus glands to go off," said Sgt. Jeremy Lee with Kentucky State Police.
One child was flown to Holston Valley with serious injuries, and the rest were taken immediately to Harlan ARH.
Another eight people were also exposed to the gas while trying to help, and had to be treated too.
"We're extremely fortunate the children were not more seriously injured than they are," said Harlan County Sheriff Marvin Lipfird.
Police are still investigating exactly how the grenade ended up in the hands of a child, but say they have more important things to worry about.
"Our concern right now is still with the victims, the children, the adults, everybody that's been exposed," said Lynch Police Chief Mike Nunley.
Police say that the child flown to Holston Valley is now in stable condition, and improving.
Officers add that the house is still very contaminated, and no one will be allowed inside until the gas is cleared out.