Oil seeping into two pits is a legacy of the Unocal oil tank site’s 70 years of operation and the first phase in cleaning up the mess.

By Janice Podsada

Herald Writer

EDMONDS — The pools are Olympic-size — Eight feet deep, 150 feet long and 15 feet wide.

But before you take a dip, bring along a dipstick and check the oil.

No swimming is allowed in these two pools, which are filling with a mix of oil and water.

Backhoes dug two huge pits last week in the lower yard at the Edmonds Unocal tank farm and uncovered a stash of underground oil. Petroleum seeped into the soil and groundwater as a matter of course during the tank farm’s 70 years of operation.

Now, the only way to remove it is to dig it out, let it ooze from the soil and fill the air with the scent of tar. Once the oil surfaces it’s vacuumed up and disposed of offsite.

The discovery of two underground pools of oil isn’t a surprise, said Mark Brearley, senior Unocal geologist. In fact, the oil is right where it’s supposed to be.

Soil samples taken from the lower yard before the pits were dug pointed to a slick of underground oil that covered from one to three acres.

During the tank farm’s years of operation, from 1922 until 1991, petroleum spills and leakage occurred, said David South, the state Department of Ecology’s site manager.

The first phase of the cleanup effort, which is being paid for by Unocal, should be completed as scheduled by the end of October, when the excavations will be closed up.

While the tank farm closed in 1991, it took almost 10 years for the cleanup effort to get under way. In the upper yard, the hillside has a fresh-scrubbed look, now that all but four of the 23 oil storage tanks have been removed.

The final four will be razed this week.

The 25-acre upper yard is being cleaned to the Ecology Department’s highest standard, which would make it available for residential use.

Unocal has already been approached by developers interested in building homes on the upper yard.

And it’s easy to see why. With the tanks gone, the view of the Edmonds Ferry dock and Puget Sound is impressive. It’s expected that the upper yard will be sold and ready for development next summer.

The fate of the lower yard, however, hangs in the balance.

Edmonds officials want it to become a regional transportation hub. Under the Edmonds Crossing plan, the Edmonds ferry terminal would be relocated to the Unocal site. But the lower yard is also being scrutinized by King County as a possible location for Brightwater, King County’s third waste-water treatment plant.

The decision on the location of Brightwater will be made in early 2003.

A full-scale cleanup of the lower yard is expected to get under way in 2004, Brearley said.

It will take that long for Unocal to develop a cleanup plan and for it to be approved by Ecology.

This summer’s cleanup effort includes mapping the extent of the petroleum contamination in the lower yard. And, as engineers have said, you don’t know until you start digging up the stuff.

You can call Herald Writer Janice Podsada at 425-339-3029 or send e-mail to podsada@heraldnet.com.