CLE ELUM -- An Ephrata truck driver's inattention is being blamed for a series of collisions Monday morning on Snoqualmie Pass that killed an elderly Idaho couple and injured five others.

Edward D. Page, 64, was driving a 2006 Peterbilt tractor truck with a trailer when it slammed into the back of a 2000 Jeep Cherokee on Interstate 90, 26 miles west of Cle Elum, according to the Washington State Patrol.

The Jeep then hit a semi, which rear-ended a sedan, which was pushed into the back of another semi, the State Patrol reported.

Page was not injured. He was wearing a seat belt in the 10:50 a.m. wreck.

However, a 68-year-old man and 73-year-old woman, both from Star, Idaho, were killed when their Jeep was smashed. Their names aren't being released until troopers notify relatives.

Eastbound traffic on I-90 is reduced to one lane for construction.

A 1999 Freightliner truck driven by Guillermo M. Calvillo, 46, of Boardman, Ore., was stopped for slowed traffic, with a 2002 Buick LeSabre behind the semi also stopped, the State Patrol reported.

A 2007 International truck was behind the sedan, and the Jeep was reportedly slowing for the traffic when it was hit by Page's truck, which had not reduced its speed, the report said.

Troopers say it was caused by "driver inattention" and are awaiting further investigation before pursuing charges against Page. The crash clogged up eastbound I-90 late into the afternoon while authorities cleared the scene.

Calvillo was not injured.

Lilian H. Skelton, 47, of Issaquah was the driver of the Buick and was taken to a Bellevue hospital for treatment. Also taken to that hospital with injuries were passengers: Lisa M. Malmin, 35, of Gilbert, Ariz.; Katherine L. Cochran, 32, of Phoenix, Ariz.; and Patricia G. Schenkel, 43, of Renton.

Ector A. Mendoza, 32, of Yakima, was behind the wheel of the International truck in the middle of the chain-reaction collision. He was being treated at an Ellensburg hospital.