VANTAGE, Wash. — Fifteen cars and nine tractor-trailers collided on Interstate 90 on Thursday, leaving nearly a dozen people injured and causing a pileup that snarled traffic on the main route across Washington state, authorities said.The crash happened just before 11 a.m. in the eastbound lanes near Vantage. Some of the 11 people who were hurt suffered serious injuries, Trooper Darren Wright said.Both directions of the highway in the area where the accident happened would remain closed until Friday because of poor visibility, the state Department of Transportation announced. Wind gusts were kicking up dust left by a brush fire that burned in the area Tuesday, said DOT spokeswoman Meagan Lott.There was no estimate on what time the stretch would reopen Friday."It's depending on conditions," Wright said. "We want everybody to be safe."The department had closed a roughly 20-mile stretch of I-90 in both directions Tuesday because of the brush fire.Wright said it's not yet known how the pileup started.The Transportation Department said there's a 15-mile detour using the Old Vantage Highway.