YAKIMA, WASH. -- A Fresno, Calif., man has died after rolling his semi tractor on U.S. Highway 97 last month, the Washington State Patrol announced Thursday.

Trinidad Madrigal Ruiz, 50, died June 23 at Yakima Valley Memorial Hospital, according to a patrol news release.

About 6 a.m. June 19, he was headed north about 18 miles south of Toppenish when the Freightliner tractor went off the road to the right and rolled on its top, troopers said.

Investigators blamed the crash on inattention. Madrigal Ruiz was wearing his seat belt and was not intoxicated, according to the news release.

A Fresno man riding with him sustained only minor injuries.