Picnic Point Explosion Update: More Than $1 Million in Damage

Damage at the Picnic Point Wastewater Treatment Facility is expected to total more than $1 million after Thursday's explosion at the site north of of Edmonds in unincorporated Snohomish County.

Meanwhile, one of five workers burned following the propane explosion was released from Harborview Medical Center in Seattle on Thursday night, said public information Leslie Hynes of Snohomist County Fire District 1. 

The injured men were believed to be employees of Apollo Inc., a Kennewick-based general contractor, according to the Herald.

The explosion was reported at 11:10 a.m. in the 6300 block of Picnic Point Road, where workers are building a water-treatment plant for Alderwood Water and Wastewater District. Contractors estimated about 60 workers were at the site when the explosion occurred as a 1,000-gallon propane tank was being loaded onto a truck to be removed from the site.

“About 300 gallons of propane remained in the tank,” said Hynes. “The tank shifted during the loading process and a valve snapped, expelling the propane. The truck driver told firefighters he yelled for everyone to get away from the truck, but the propane immediately ignited and exploded.”

More than 50 firefighters from Fire Districts 1 and 7 and Lynnwood, Mukilteo and Snohomish County Airport fire departments responded. “The propane tank, truck and the ground surrounding it were in flames when firefighters arrived,” Hynes said. “An adjacent construction trailer was burning. We also had fires in two two-story buildings that are under construction.”

Firefighters had the fires under control by about 1 p.m., but crews continued to battle small brush fires in a wooded area behind the site throughout the afternoon.

Hynes said the damage total includes that to two buildings under construction—the propane tank and truck, the construction trailer and building materials. The propane explosion had a blast zone with a 300-foot radius, according to investigators from the Snohomish County Fire Marshal’s office.

All five of the injured workers were inside the larger of the two buildings damaged by the propane explosion. Fire investigators believe a second explosion most likely occurred inside the building when flames from the first blast ripped through the building and ignited flammable vapors from a process that workers were using to apply paint.