Updated

Three girls from a synchronized swim team fainted simultaneously and went under at the deep end of a public pool in this Seattle suburb while practicing holding their breath, team leaders said.

Others around the indoor pool at St. Edward's State Park also felt faint and dizzy, and fire officials asked the Seattle-King County Public Health Department to check the chlorine level in the water following the frightening episode Monday.

The swimmers, ages 11, 12 and 13, had been in the Kenmore 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.

The drill was "basically a warm-up" that the girls had been doing for months, and older teammates who had been swimming laps at the same time complained that their hands tingled, Abel said.

"From the preliminary findings, it appears there were some high chemical levels at the pool," Abel said. "We're at the height of our season and the girls are in great physical shape. This was a very fluke thing."

Penner said air at the pool was tested and did not appear to be abnormal, but Abel said tests indicated unusual chemical levels in the water.