MARYSVILLE, Ohio - Fourteen hotel guests, including some in critical condition, were hospitalized Saturday after a "life-threatening" carbon monoxide leak at the hotel's indoor pool.

Marysville Police Chief Jay Riley told ABC News that investigators discovered "life-threatening levels of carbon monoxide in the pool area." Officials are still investigating the source of the leak.

Several 911 calls were made Saturday evening reporting people found unconscious around the pool area of the Hampton Inn in Marysville, Ohio, according to police. Marysville is a suburb of Columbus.

Police said one of the calls mentioned an unconscious 2-year-old girl found in the water.

People at the hotel were complaining of dizziness and a burning sensation in their throats.

Eleven people -- six of them children -- were treated at Memorial Hospital in Marysville for hazmat exposure symptoms.

Seven patients were reportedly transferred to tertiary care facilities, and two of them are in critical condition. The other five are "serious but stable," hospital spokesperson Melanie Ziegler said.

Three people were sent to Grady Memorial Hospital, with two in stable condition and one in critical.

Two patients were evaluated at the scene, police said. The ages of the patients were not immediately known.

"The Hampton Inn Marysville is fully cooperating with the local authorities as they investigate this incident," a hotel spokesperson said. "Please contact the Marysville Fire Department for additional information."