Multnomah County, OR- A young boy was recovering from carbon monoxide poisoning Sunday after he stopped breathing while swimming near the back of his family’s idling boat, authorities said.

It happened shortly before 4 p.m. at Chinook Landing Marine Park on the Columbia River near Fairview. According to the Multnomah County Sheriff’s Office, the boy was wearing a life jacket while playing in the water near the boat’s exhaust outlet for some time. When the family went to move the boat, they found the boy had stopped breathing, and they pulled him from the water, the sheriff’s office said.

By the time medical help arrived to the boat dock, the boy had already started breathing again. He was taken to Providence Portland Medical Center for treatment of carbon monoxide poisoning in a hyperbaric oxygen chamber.

The sheriff’s office said the boy’s chances for survival might have been significantly diminished had he not been wearing a life jacket.