A 66-year tradition of steel fabrication on the Napa River is coming to an end with Trans Bay Steel Corp.’s move from the former Napa Pipe property to an industrial park in Fairfield.

What started as Basalt shipyard at the start of World War II, then morphed into the mighty Kaiser Steel operation employing 1,700, is ending with Trans Bay packing up 53 workers for the trek through Jamieson Canyon.

Over the decades, the 152-acre property south of Napa has produced a flotilla of small boats, enough large-diameter oil and gas pipes to ring the planet, steel tunnels for BART, oil drilling platforms and missile silos.

Trans Bay Steel finished a fabrication project last week for the new San Francisco-Oakland Bay Bridge. Truckloads of heavy production equipment are being packed for shipment to Solano County.

“It’s like moving your home, your family,” said Bill Kroplin, a Trans Bay owner.

Co-owner Bill Kavicky is thankful that Keith Rogal and Napa Redevelopment Partners, who paid more than $40 million for the Napa Pipe acreage two years ago, allowed him time to find another site.

But Kavicky barely suppresses bitterness that Napa County no longer values his gritty industrial operation. Although his company paid a ton of sales tax, “I don’t think anybody knows we’re here,” he said.

When Oregon Steel put Napa Pipe up for sale in December 2004, Kavicky tried to buy 70 acres of industrial buildings along the riverfront. “We were always geared up to fill the void and continue on,” he said.

Instead, Oregon Steel sold to Napa Redevelopment Partners, which was able to pay cash for the entire 152 acres. The Napa plant was too far from Oregon Steel’s steelmaking operation in Portland and lacked modern technology, the company said.

In short order, the new owners announced plans for 3,200 homes and a half-million square feet of light industrial areas, creating a contemporary riverfront development on ground where heavy steel once reigned.

The county’s draft general plan for the area looks at a variety of development options. None of them call for the retention of Trans Bay Steel.

Steel fabrication was a noble part of Napa’s economic heritage, but times have changed, Rogal said. Wine and clean industry are today’s big players, forcing heavy industry to lower-cost areas, he said.

Steel was once “the right thing at the right time,” but “it isn’t where we’ve been for decades,” Rogal said. His partnership made sure that Trans Bay had time to complete its contracts for the Bay Bridge, he said.

Trans Bay will be moving to a 140,000-square-foot plant on Cordelia Road, a short distance from interstates 80 and 680 and Highway 12. The Fairfield property, which was formerly occupied by a fireplace accessory manufacturer, belongs to Adobe Lumber. Adobe’s owners, Napa’s Michael DeSimoni family, are giving Trans Bay a lease-purchase option, Kavicky said.

The facility is being modified to handle steel components weighing thousands of pounds. Instead of barging fabrications down the Napa River to job sites, Trans Bay will use trucks and rail, Kroplin said.

There is a night-and-day difference in the ways that Napa and Solano counties regard heavy industry, Kavicky said. Fairfield officials “like the fact that jobs are moving there,” he said.

After finding the property in August, Trans Bay concluded the deal with Adobe in two days, then quickly wrapped up permitting issues with the city of Fairfield, Kavicky said.

“The atmosphere we’re moving into is far and away beyond what I would have imagined,” he said.

Trans Bay is retaining all 53 of its workers, many of whom live in Napa. They will continue to draw a paycheck while Trans Bay gears up to resume work before year’s end, Kavicky said.

Trans Bay expects to ramp up its workforce to close to 100 in the next few years as California begins spending to update its aging public works infrastructure, he said.

In 2002, Trans Bay settled charges filed by the U.S. Equal Employment Opportunity Commission that it had discriminated against and exploited welders imported from Thailand.

The company agreed to employ dozens of welders who had been promised Napa jobs but had been diverted to lesser work in Los Angeles by a labor importer.

A dozen of the 48 Thai welders involved in the settlement are still with Trans Bay today and will be moving to Fairfield, Kroplin said.