The new ferry terminal at Mukilteo is located on the site of what was once an Air Force fuel tank farm.  There is not much left to give that role away anymore but the shape of the tanks is still visible on the ground.  One of them still seems to have some of the old tank material left over too.  Not sure what the story is with cleaning up the site and removing the material but it isn’t cordoned off so I guess it has been decontaminated.