On Halloween Eve, Port of Seattle staff gathered to celebrate what has been some Highline residents' scariest fear.

As TV cameras rolled, commission president Pat Davis pulled up in a fill-dirt truck from Gary Merlino Construction to deliver the final ceremonial load of dirt for the 13-story third-runway embankment at Sea-Tac International Airport.

The truck was one of the fleet that hauled 17 million cubic yards of dirt to the site over five years.

During the past three years alone, they made 394,000 trips on our freeways-394,000!

The project was so massive that Merlino partnered with two other firms to form TTI (The Three Italians) Contractors to fulfill the contract.

Following the final unloading, Davis declared, "The dirt is cleaner than dirt found on a kindergarten playground."

That statement wasn't as reassuring to me as Davis had hoped after my mind flashed back to another local environmental story.

While residents rallied against feared pollution coming east from the airport, arsenic and lead had been silently floating up from the south for a century. An Asarco copper smelter near Tacoma spewed the stuff out of its smokestack from 1890 to 1985.

State law requires a mandatory cleanup when more than 20 parts of arsenic per million parts of soil are present.

But when initial readings on undisturbed forested lands around Des Moines, Normandy Park, Burien and Federal Way showed 40 out of 45 samples were above that standard, a compromise was needed.

After all, you can't bulldoze away the top six inches of dirt from a major urban area.

Fortunately, tests on developed areas where the soil had been mixed around showed lower levels of arsenic.

I don't want to scare little kiddies or their parents so I will mention public health agencies have worked with schools and daycares. I am confident that the dirt is clean at your local kindergarten playground.

But let's get back to the top of the runway embankment.

Port CEO Mic Dinsmore backed up his president. He bragged to a TV reporter that the Port had produced one of the cleanest and most environmentally sound public works projects in the state.

That reminds me of an old story attributed to 1950s presidential candidate Adlai Stevenson:

A preacher is walking down a country lane and spots a sweaty farmer who has just finished clearing a rocky field.

"What a great example of the Lord's work," he exults to the farmer.

"Well, Reverend, you should have seen the field when the Lord had it all to himself," the farmer replies.

The fact is the Port had a lot of (unwanted) help in making the third runway one of the cleanest airport projects in the nation.

Keeping the airport's tremendous flow of stormwater out of nearby creeks is a major accomplishment. It is even more daunting during one of those 100-year rainstorms that occur every couple of years lately.

And having had an engineer as a father, I appreciate a difficult project done well.

Also having learned to swim at a pool whose former location is now buried deep in the middle of the runway. I appreciate what a massive undertaking it was to turn a deep valley into a high plateau.

So, congratulations to the Port.

But also congratulations to Highline cities and their citizens who nudged with lawsuits and appeals the state Ecology Department, the Army Corps of Engineers and the state Pollution Control Hearings Board into requiring the runway to be as clean as a kindergarten playground.

Eric Mathison can be reached at hteditor@robinsonnews.com or 206-388-1855.