KANSAS CITY, Kan. -- A Kansas City, Kan., house fire sent 10 people, including eight children, to the hospital with carbon monoxide poisoning Wednesday morning.

A resident at the house at 38th Street and Haskell called 911 after many of them started feeling sick. When fire crews arrived, they said they found a small fire in the attic, that may have been smoldering for hours.

A neighbor reported seeing smoke two hours earlier, but said they did not see enough for call authorities.

"They started to get high carbon monoxide levels on everybody, especially some of the children being so young," KCK Fire Chief Craig Duke said. "The carbon monoxide (we) have one with 30 parts per million, 10 parts per million is the cutoff level. Anything above that you start to become concerned."

There were 13 people inside the home at the time of the fire. Some of the children taken to the hospital may need treatment, but all are expected to recover, fire officials said.