An encampment fire underneath Seattle’s Ship Canal Bridge caused traffic backups along Interstate 5 Wednesday morning. KIRO Newsradio’s Sam Campbell says that fire crews have extinguished all but the embers of the fire under the bridge, but lanes continued to crawl past emergency vehicles throughout the morning. Traffic is expected to return to normal as crews continue to get the fire extinguished. Seattle Police Department officials say they don’t know how the fire started but they knew there was combustible materials inside the homeless camp under the bridge. Firefighters and police responded after reports of smoke and fire from drivers on the bridge, and firefighters say they saw billowing smoke and heard popping from lithium-ion batteries, making them call in for backup.