A Layton boy died from asphyxiation Friday morning while riding in his parents' van near The Dalles, Oregon.

Michael Szczepanek Jr., 11, died after exhaust fumes apparently entered the rear of the vehicle where he was sleeping, causing the asphyxiation.Several of the 12 people in the van had experienced flulike symptoms while driving through the night. Family members stopped for breakfast Friday morning in The Dalles and were unable to wake Michael Jr., said Steve Thompson, an LDS Church bishop who is housing the family in The Dalles.

The boy was traveling in an older model Dodge van with his parents, Michael and Shanna Szczepanek, and his six brothers and sisters. The family was on its way to Seattle to visit grandparents. Shanna Szczepanek's brother and his wife and young child were also in the vehicle.

All of the vehicle's occupants were treated for carbon-monoxide poisoning at Mid-Columbia Medical Center and released Friday.