About 4,310 Pacific Power customers in Medford were without power for several hours Tuesday after a Mylar balloon drifted into a substation on South Stage Road and caused several fuses to blow, company officials reported.
An explosion was reported at 11:33 a.m. Tuesday at the substation, 2860 South Stage Road, west of Medford.
"They certainly acknowledge that there was a boom," said Tom Gauntt, Pacific Power spokesman, adding that the damage included some blown fuses.
Medford Fire-Rescue responded but left when no fire was seen.
While performing repairs, Pacific Power employees found the remaining shreds of the foil-like balloon.
"Essentially that creates a conductor between the wires," Gauntt said. "That does happen. It's unlikely that someone did it on purpose. All you need is a couple that get in the wrong place."
Traffic lights at Stewart Avenue's intersections with Columbus Avenue and Lozier Lane went out, turning the corners into temporary four-way stop signs.
Medford police said traffic assistance from patrol officers was unnecessary.
Electricity also stopped flowing to several west Medford streets, including McKenzie Drive, Andrews Road, Elm Street, Dakota Avenue, West Ninth Street and Chestnut Street.
Neighborhoods bordering the South Stage Road stretch also were affected.
"Pretty much along that corridor of (South) Stage Road," Gauntt said.
Power was fully restored by around 2:30 p.m.
Gauntt said eight outages statewide in 2012 stemmed from Mylar balloons, cutting power to about 1,900 customers.
"It's not often," Gauntt said. "It's not as frequent as birds or squirrels or even car crashes."
Reach reporter Ryan Pfeil at 541-776-4468 or email@example.com.