KENMORE, Wash. -- Seattle-King County Health Department inspectors have found nothing wrong at the Kenmore swimming pool where three synchronized swimmers fainted and sank, nearly drowning on Monday.

A team that conducted a preliminary investigation on Tuesday found normal levels of fresh air, carbon dioxide and oxygen, a department spokeswoman told KIRO 7 Eyewitness News.

Hilary Karasz said tests also showed normal chlorine, ph and clarity levels and no mechanical problems at the pool at St. Edward's State Park.

Karasz said the investigation will continue and that investigators will interview everyone involved.

The girls, ages 11, 12 and 13 years old, simultaneously fainted and went under while swimming in the deep end of the public pool on the north side of Lake Washington.

The girls were attending practice for the Seattle Synchronized Swimming Club and were practicing holding their breath when the accident occurred, team leaders said.

Others around the indoor pool said they felt faint and dizzy.

The girls had been in the pool about 15 minutes when they began having difficulty, head coach Julie Abel said.

"One of them was hanging on a rope and a coach saw her slip under water," team president Craig Penner said. "The coach jumped in and pulled her out, then looked back and saw two other girls on the bottom of the pool."

A lifeguard and another coach aided in the rescue.

A fourth girl swam to the side of the pool and said she was dizzy and unsure where she was or how she got there, and the mother of a team member blacked out after bending over the water, Penner said.

The three girls who passed out were under water less than a minute before receiving cardiopulmonary resuscitation, and all three were breathing and conscious by the time emergency aid crews arrived, the team president said.

As a precaution, two spent the night at Evergreen Hospital Medical Center in Kirkland and the other was at Children's Hospital in Seattle.