As you might expect of the company that brought the world the automated assembly line, Ford Motor Co. even aims for efficiency when it's tearing things down.

For weeks now, the automaker has been cataloging the St. Paul plant's wares down to the staplers, spotting what can be transferred to other Ford plants, what should be scrapped or sold to auctioneers and what hazardous materials in the building -- mercury switches, leftover paint -- require special disposal. An environmental consultant will start boring holes through the main plant's thick concrete floor sometime next year to take soil and air samples, as part of an ongoing investigation into contamination at the 86-year-old factory on the bluffs above the Mississippi.

"It's unfortunate, but one of the things we try to do is develop a standardized process," said Roger Gaudette, Ford's decommissioning czar. "You don't want to have to re-create the wheel every time you do that."

The last Ranger pickup truck is expected to run off the line Friday morning. Then Ford's plan is to raze most of the buildings, including the original 1925 building, designed by noted Detroit architect Albert Kahn and with a red tile roof and ornate light fixtures. Because a 1960s expansion dramatically altered the landmark building, it didn't qualify for the National Register of Historic Places.

Demolition is scheduled to start by summer, and it will likely take a year for crews to knock the place down, chew up the concrete and break up the vast expanses of asphalt. Soil cleanup will likely run well into 2014 and possibly beyond.

It's a process with which the Detroit automaker is all too familiar. Ford has decommissioned 15 plants over the past decade, razing four of them itself. The company intends to hire a construction manager to oversee the demolition of the St. Paul plant, Gaudette said. It will likely bid out the job to a select group of preapproved companies it has worked with in the past, a group that includes Walbridge, the Detroit construction company that worked on Ford's Rouge Complex in Dearborn, Mich.

Much of the gear inside the cavernous plant will probably be scrapped, said Brad Bystrom, the plant's longtime engineering manager, since much of it is tailored to building the Ranger. A Ranger that Ford is manufacturing in Thailand is a totally different vehicle, he said.

Walking past a line of nearly finished candy-colored pickups inside the plant, Bystrom gets wistful about the place. He had other career opportunities but stayed 27 years.

"You work so hard to keep it running, and now it's going to be taken apart," Bystrom said. "The original building was just gorgeous."

'Stunning' building

A few scattered vestiges of the Ford plant's original self still exist, mostly on the northwest corner facing the Mississippi, where visitors can still see the building's red tile roof and globe-like light fixtures. Old postcards show a long, stately, one-story structure with a Mediterranean design and classical touches such as fluted half-columns. Facing the river was a procession of large windows, allowing people to see into the final part of the assembly line and watch the finishing touches being put on the cars, said Charlene Roise, president of Hess Roise and Company.

"It was a stunning building," Roise said.

Ford hired Roise a few years ago to study the historical significance of the buildings. The 1960s remodel, which added an extra bay facing the river and covered the windows, changed the plant's original character too much for the National Register.

"With this property, just too much had happened," Roise said.

One element that survived is a frieze that Ford moved from its original spot and stuck on the end of the new addition. Flanked by two relief carvings of noble laborers -- one holding a car, another a tractor -- is the saying "Excellence is never granted to man but it is the reward of labor."

Roise said she hopes Ford salvages some of the artifacts so the site's future developer can incorporate them into whatever gets built there.

Ford workers joked about being "inspired" by the lofty carving, but it remains one of the most recognizable features of the original plant.

"Everything went, but for some reason that stayed," Bystrom said.

The real work: cleanup

Wrecking is the easy part. The main challenge is cleaning up the site -- a job whose size remains a mystery at this point.

Ford typically cleans decommissioned sites to an industrial standard, as it plans to with this site. But the environmental assessment was delayed because Ford extended the plant's operation longer than it once planned, and it won't formulate a cleanup plan until sometime in 2013.

Arcadis, the Netherlands-based environmental consultant that has been probing the site for Ford for years, likely will handle the actual cleanup too. It declined to comment.

The Minnesota Pollution Control Agency (MPCA) said the pollution is typical for a heavy industrial site. There's lead, mercury, arsenic, heavy metals, chlorinated solvents and petroleum in the soil -- the usual suspects, said Amy Hadiaris, an MPCA hydrogeologist working with Ford on the cleanup.

Shanna Schmitt, project manager for the Ford plant in the agency's Voluntary Investigation and Cleanup program, said the Ford site is "not nearly" as dirty as the old ammo manufacturing site in Arden Hills, a Superfund site where the Minnesota Vikings want to build a new stadium.

As part of the investigation, Ford is taking another look at its old disposal site, a dump now covered by a parking lot down by the Mississippi near the site's steam plant, Hadiaris said. For about 40 years workers used to dump barrels of paint sludge and other waste over the bluff onto a sandy flat area. There's about 20 to 25 feet of waste, Hadiaris said.

Then the spot became a demolition landfill where blocks of waste concrete were dumped, creating an additional 40-foot layer. Then it was paved over.

Hadiaris said most of the pollutants already have seeped out of the site and were washed down the river decades ago.

"It's probably down in the Gulf of Mexico," she said. "From our perspective it is not a ticking time bomb."

Clean enough for homes?

The biggest question mark, the MPCA said, is what's under the main building itself. The agency figures the damage probably isn't catastrophic because ongoing groundwater samples would have shown that, but haven't.

A ring of about a dozen groundwater wells were installed around the plant's perimeter in 2007. They're monitored twice a year.

So far, a few wells have shown very low levels of a range of common petroleum compounds, such as diesel fuel, Schmitt said. Occasionally, they'll detect trace hits of various other chemicals. But nothing that indicates a disaster.

Schmitt said that in her mind, it's "definitely a possibility" that parts of the site can be cleaned to residential standards. That's a crucial point that will help determine the site's next life.

"That is going to drive the marketing strategy. Can we clean parts of this site to residential? That's the big question right now," Ford spokeswoman Stefanie Denby said. "We're all very anxious ourselves."

Jennifer Bjorhus • 612-673-4683