An estimated 40,000 gallons of sewage spilled from the Vashon Wastewater Treatment Plant on Tuesday due to a clogged sewer line outside the plant, according to King County officials.

County officials got a call from a neighbor about a sewage smell near the plant around 4:30 p.m. on Tuesday. By 10 p.m., county officials said, crews had pumped the line and plugged it so as to prevent more spillage.

Visual inspections suggest the spill was contained to a dry creek bed where it was initially spotted and did not reach Puget Sound. The county is investigating to determine whether the clogged pipe belongs to the county or the Vashon Sewer District.

Signs closing the area to the public were immediately posted to protect public health, and water samples were collected for testing at the treatment plant and an accredited laboratory. A vactor truck worked well into the night to gather all signs of wastewater. Crews were onsite again Wednesday completing the cleanup.