Airport spokesman Perry Cooper says 1,000 to 1,500 passengers in the C and D concourses and central terminal had to be rescreened later through security checkpoints.
Port of Seattle police and Transportation Security Administration officials found the passenger at about 9 p.m. He was questioned and released. Cooper says the issue was a misunderstanding, "not anything of a security concern to passengers."
After the man was cleared, passengers began the rescreening process. Cooper says the checkpoint backup was cleared by about 10:30 p.m. He says airlines typically try to accommodate passengers caught in such a delay.