Call it Lake Elmo’s Big Dig.

Beginning this summer, enough garbage will be removed from the Washington County Landfill to fill the Metrodome five times.

“Look at this — it’s the size of a football stadium,” shouted Jeffrey Lewis over the racket of bulldozers as he pointed to an enormous pit this month. “And this is only one-eighth of it.”

Lewis, who manages landfill cleanups for the state, is chasing an environmental bogeyman — PFCs, or perfluorochemicals — made by 3M Co.

The clear, odorless PFCs are seeping into the soil from 2.5 million cubic yards of garbage. So Lewis is overseeing the effort to dig up the entire 60-acre site, install liners and replace the garbage.

At $21 million, it easily will be the most expensive landfill cleanup in state history.

In addition, PFC cleanup projects have begun, or will begin soon, at dump sites in Oakdale, Woodbury and Cottage Grove. At those sites, contaminated soil will be dug out and trucked to a specially built landfill in Rosemount.

By most standards, those cleanups would be considered large, with a total of 126,000 cubic yards of dirt — 6,300 truckloads — to be removed.

But those projects are tiny compared with the Lake Elmo project, massive because of how the PFCs were dumped — scattered randomly in a 60-acre landfill, mixed with domestic garbage that was piled 40 feet deep.

It isn’t the first time the Lake Elmo landfill has been cleaned up.

In the early 1970s, the site was the primary landfill for St. Paul and several suburbs. One customer was 3M, which disposed of sludge left over from manufacturing PFCs.

When the landfill was full in 1975, it was covered with topsoil and planted with grass. Officials thought they’d never have to deal with it again.

In 1995, traces of solvents were found in nearby wells, leaking from the landfill. The Minnesota Pollution Control Agency stretched plastic sheeting over the landfill to keep rain from seeping down, then covered the plastic with dirt and planted grass, again.

The cost was $3 million. The problem was solved — or so they thought.

Then came 2004 — the year the forgotten landfill came back from the dead.

For the first time in Minnesota, officials tested well water for PFCs. The chemicals eventually were found in the drinking water of about 67,000 people, in an area that included Oakdale, Woodbury, Cottage Grove and Hastings.

It was unclear — and remains unclear — how dangerous traces of the chemicals really are.

In megadoses, PFCs cause cancer, thyroid problems and birth defects in mice. But the traces in water were so small that 3M said — and state officials agreed — that the PFCs were harmless. This claim was validated by a Washington County judge this year when she rejected claims that the PFCs hurt anyone.

Most of the $21 million for the latest cleanup of the Lake Elmo landfill is to be paid by the state.

3M kicked in $8 million even though it is not legally liable. 3M is paying for all cleanup costs at the other three sites; the company won’t disclose the total expense.

Few Complaints From Neighbors / Early in August, Lewis stomped across the acres of rotting trash in Lake Elmo and paused on the lip of what looked like a small canyon.

The cutaway layers of garbage seemed like an archaeological dig. The food, paper and cardboard had rotted away, leaving a colorless wall of gunk.

“What you end up with is mainly plastics and glass,” Lewis said.

There were tell-tale signs that 3M had used the landfill. “Look at that — rolls and rolls of 3M tape,” said site engineer Peter Tiffany, looking at streamers of audiotape fluttering in the wind.

“It’s like Mardi Gras,” wisecracked MPCA spokesman Ralph Pribble.

The cleanup plan is similar to emptying a puddle, building a bathtub below it and refilling it with the water. Contractors will move the garbage out, section by section, then build liners and put the garbage back in.

As of mid-August, workers had dug up the first of eight sections of the landfill and were installing a 10-layer drainage system before they would redeposit the garbage.

Tiffany said a few neighbors asked why the offending garbage wasn’t hauled away. The reason is cost, he said — it would have been three times as expensive.

And the section-by-section empty-and-refill method avoids the specter of loading 2.5 million cubic yards of garbage onto trucks — enough truckloads to make a line from St. Paul to Chicago.

The work has drawn few complaints from neighbors.

“I have not noticed a thing, and I am very surprised by that,” said Jeff Downs, who lives across Jamaca Avenue from the landfill.

“They dug it up once before and put on a liner,” Downs said. “It was a little more ripe then. Now there is a smell of dirt, but nothing offensive.”

Tiffany showed the layers of 60-mil plastic “geo-synthetic membrane,” plastic netting and padding that had been installed. Below them was a 2-foot layer of clay.

There are three plastic layers to collect liquids, each with its own separate pump. When PFCs or anything else leaches out of the trash, they will collect in a drainage system underneath.

Trucks will then haul the PFC-containing liquid to treatment plants.

“It’s a state-of-the-art system,” spokesman Pribble said.

Lewis said the goal is to dry the trash until no more liquid seeps out.

The work should be completed in two years. By then, 60 acres of trash will be concentrated into 25 acres and piled 60 feet above the current ground level — about the height of a six-story building. Overall, the trash will be piled 90 feet deep.

The super-mound will be covered with 2 feet of sand and 2 feet of topsoil. It will be planted with grass — yet again — to be laid to rest as a graveyard for the most expensive pile of trash Minnesota has ever produced.

How long will that system keep pollution out of the water? Not forever — but close enough.

Tiffany cited a study that predicted such a system could be effective for 1,000 years.

The Pfc Trail

1947: 3M begins manufacturing PFCs — perfluorochemicals — for household products.

1970s: 3M stops dumping PFCs in landfills.

2000: Reports increase of PFCs discovered in animals and people worldwide.

2002: 3M stops making PFCs; officials develop test for PFCs in water.

2004: PFCs detected in water in Lake Elmo and Oakdale.

2005: DuPont Corp. pays $300 million for PFC contamination in Ohio.

2006: Tests developed for detecting PFBA, another form of PFC.

Jan. 20, 2007: PFBA discovered in 15-mile-long plume running from Lake Elmo to Hastings.

June 7, 2007: Minnesota Department of Health says there is no increase in health problems in the affected area.

June 20, 2007: Judge rules against “class action” status, so plaintiffs must sue 3M individually.

Aug. 17, 2007: PFCs found in local fish. Officials recommend limiting fish consumption.

Jan. 17, 2008: Health Department says PFC levels in water too low to be a health threat.

Dec. 19, 2008: A Washington County judge rules, in effect, that PFCs did not injure water drinkers.

May 4, 2009: Trial begins, limited to 3M negligence and damage to property values.

June 17, 2009: Jury rules for 3M, saying property damage and negligence were not proved.

Summer 2009: Cleanup of PFCs begins at Washington County Landfill, Lake Elmo.