Even after a cleanup, soil along the Portland Harbor is the contaminated gift that keeps on giving.

The BNSF Railway Company agreed yesterday to pay the Environmental Protection Agency a $37,500 fine for illegally storing and transporting three truckloads of dirt it dug up from the edge of the McCormick & Baxter Superfund site.

The soil was polluted with pentachlorophenol, a pesticide used at McCormick & Baxter as a wood preservative to coat telephone poles and railroad ties. EPA studies say it causes cancer—other effects of exposure can range from skin irritation to falling into a coma.

The McCormick & Baxter site is a 41-acre former wood-treating plant, located along the the Willamette River just south of the University of Portland. It closed in 1991, and was identified by EPA as an "early action" Superfund site in 1998, two years before the rest of the Portland Harbor identified as a federal pollution project. Its soil, polluted with pentachlorophenol and creosote, was capped with clean soil—one of the few Portland Harbor Superfund upland locations to be certified as finished.

But the contamination is still there. EPA says BNSF Railway Company excavated and removed 36 cubic yards of soil near the cap boundary in 2009, as part of a project stabilizing the ground for a train pull-off. EPA cited BNSF for not labeling the dirt as polluted, then improperly storing and transporting it, all violations of federal hazardous waste law.

BNSF's agreement to pay the $37,500 fine is not an admission of wrongdoing.