By the time the job is done, workers will have removed about 50,000 cubic yards of oily fill – enough to pack the stack of the Museum of Glass more than three times.

The bunker-grade oil that contaminates the area has been traced to a long-disused railroad fuel line that was installed in the early 1900s. The line ran parallel to East D Street, east of the waterway.

The goal is to stop the oil, an environmental toxin, from seeping into the 11/2-mile channel, said Marv Coleman, who oversees the project as on-site manager for the state Department of Ecology’s toxics program.

“We’ll be done by next summer,” he said.

The Foss Waterway is the centerpiece of Tacoma’s downtown revitalization and was the focus of a $103 million Superfund cleanup, completed about two years ago.

“This will have a profound effect on improving the water quality in Thea Foss,” said Coleman. “You actually had this stuff floating around,” he said of the oil, which leaked out of the pipeline.

The $3.2 million project, now in its first phase, is visible from the Highway 509 bridge. The cleanup area extends north along East D Street for nearly half a mile to East 15th Street.

Because the pipeline belonged to the railroad, the BNSF Railway Co. has hired contractors to do most of the cleanup work.

However, the railway is not the only liable entity. Under the authority of the state’s Model Toxics Control Act, state Ecology Department officials also required cleanup commitments from the City of Tacoma, the state Department of Transportation and a neighborhood business, the Home Electric Co. The settlement agreement, signed by all parties, was recently approved in Pierce County Superior Court.

Gus Melonas, railway spokesman, refused to discuss the cost of the cleanup, but said his company will take whatever steps are necessary to protect the environment. He also said there is no current environmental threat.

Originally, railroad workers laid the pipeline to carry bunker oil from a dock near East 15th Street to a former railroad yard at East D and East 23rd streets, Coleman said.

The railroad stopped using the pipeline in the 1960s, according to a brief history included in a cleanup plan prepared for BNSF by GeoEngineers Inc., an environmental consulting firm.

In 1995, state Department of Transportation officials discovered the problem oil when they excavated a storm-water retention pond north of the Highway 509 bridge, said Ron Landon, a Transportation Department manager.

“That was the opening salvo to this whole thing,” Coleman said.

Now, in agreement with the railroad, BNSF is digging up the contaminated fill in the area of the pond and the DOT is spending $124,000 to rebuild it, Landon said.

Over the past few years, portions of the pipeline have been removed or cleaned out and capped, Coleman said. Workers also have removed a few related oil storage tanks and encapsulated others, he said.

Several years ago, city officials blamed the pipeline for tarlike globules of oil that spilled from a stormwater outfall near Johnny’s Dock Restaurant.

To solve that problem, in 2004 city officials spent $800,000 to excavate the area and rebuild the drain, said Calvin Taylor, a hydrogeologist who works for the city. The money was drawn from surface water collection fees.

The contaminated material now being removed is trucked to LRI’s Graham landfill for disposal, Coleman said.

Much of the sullied fill is wood waste, probably deposited early in Tacoma’s history when sawmills lined the waterfront, Coleman said. At the time, people tried to build up the Tideflats to create more usable land.

Susan Gordon: 253-597-8756