A 4-year-old boy drowned Thursday in a wave pool at the Paramount Great America amusement park in Santa Clara, authorities said.

The boy was unconscious when park lifeguards pulled him from a two-foot-deep section of the Great Barrier Reef, according to Bill Lentz, Great America's general manager. The 355,000-gallon attraction, which opened over Memorial Day, simulates the sensation of ocean waves.

Lentz said the park provides life vests and inner tubes for visitors to use in the wave pool, which does not have age or size restrictions. He said he did not know if the boy who drowned knew how to swim or if the boy was being supervised at the time of the accident just before 2:30 p.m.

"Our thoughts and prayers are going out to the family in this unfortunate situation," Lentz said.

The lifeguards and Great America emergency workers administered CPR on the child until Santa Clara County paramedics arrived, he said.

The boy was taken by ambulance to Kaiser Permanente Medical Center in Santa Clara, where he was pronounced dead after additional attempts to resuscitate him failed, said Dave Parker, a spokesman for the Santa Clara County Fire Department.

The wave pool and several adjacent sections of Great America's 13-acre Boomerang Bay water park were cleared and closed so Santa Clara police and park security officers could investigate the incident, Lentz said.

The last reported fatality at Great America happened eight years ago when a 12-year-old boy fell from the Drop Zone Stunt Tower.