Fire breaks out in underground pipes at Brightwater Treatment Plant

WOODINVILLE — Dozens of firefighters responded to a major fire in underground pipes Tuesday afternoon at the Brightwater Treatment Plant.

Around noon, workers were fusing plastic piping, sparking flames that shot down pipes extending 60 feet underground, Snohomish Regional Fire & Rescue spokesperson Peter Mongillo said.

Two employees were being evaluated for smoke inhalation at the scene.

The part of the plant that caught fire — an “aeration basin” — is under construction, so plant operations weren’t affected, said Marie Fiore, a spokesperson for King County’s Wastewater Treatment Division.

Heavy smoke was billowing from the pipes, which are partly exposed to the open air, around 12:30 p.m.

“It’s not under control, Mongillo said at the time. “… It’s intensifying as well.”

Fire crews were standing back, in the 90-degree heat, until a technical team could arrive to deal with the fire in a confined space.

Opened in 2011, the Brightwater Treatment Plant is considered an “integral part of King County’s regional wastewater treatment system,” according to the county website.

The 114-acre plant, built at a cost of $1.8 billion, collects wastewater from northeast King County and southeast Snohomish County. Once treated at the plant, the water either goes into Puget Sound or it’s used for industrial purposes or irrigation. The plant can treat an average of 36 million gallons of wastewater per day.

Brightwater uses a “state-of-the-art membrane filtration system,” and the plant’s system “includes 13 miles of pipeline built in underground tunnels,” according to King County.

Hazmat crews from around the region were dispatched to the scene.

“We’re going to be here for quite a while,” Mongillo said around 12:30 p.m.

A 13-member technical team — equipped to deal with fires in confined spaces — was on the scene by 1:30 p.m. Smoke from the pipes appeared to disappear around the same time.

Fire departments at the plant included Snohomish Regional, South County, Monroe, Bothell, Everett and Woodinville.

The fire was reported out at 3:14 p.m.

The extent and cost of the damage was unclear Tuesday.

Caleb Hutton: 425-339-3454; chutton@heraldnet.com; Twitter: @snocaleb.

Ta’Leah Van Sistine: 425-339-3460; taleah.vansistine@heraldnet.com; Twitter: @TaLeahRoseV.