The once-blighted American Steel factory has become one of the most influential components of West Oakland’s industrial arts scene — home today to some 200 artists who toil away at cast iron sculptures, mutant vehicle cars and other provocative works.

But for the last 18 months, the inhabitants of American Steel Studios have had a cloud hanging over their heads. Their lease expired in July 2014, leaving master tenant Karen Cusolito on a month-to-month contract with the landlord, Maurice Kanbar, and his holding company, KS Properties One LLC.

In the intervening months, Kanbar put the factory building, its adjoining warehouse and several adjacent parcels on the market. He advertised the entire 12.6-acre swath of land for $30 million to several prominent Oakland developers, suggesting they raze American Steel and quilt the area with new offices or retail.

Though Kanbar hasn’t found any takers, some artists worry that he’ll eventually clinch a deal — and give them the boot. The building is zoned for industrial or commercial use, so it could ultimately be transformed into a tech campus, a big-box store or an office park.

“I talk about it with the other tenants in our little space area,” said Grant Irish, a sculptor who began working at the studio in 2011.

“There’s a big concern in the Bay Area, and in Oakland in particular,” he added. “Where would we go?”

Filling empty space

The American Steel factory, which for decades fabricated a variety of metal products, was virtually empty by the time Cusolito, a large-scale mixed-media artist, arrived in 2005. She’d been commissioned to build a 46-foot-tall sculpture of a woman and child for Burning Man, and the warehouse had all the accoutrements she needed: 5-, 7-, and 10-ton bridge cranes, vast floor space and drive-through truck access.

“It seemed like a pretty logical place,” Cusolito said. She stayed there working on the project for eight weeks.

Cusolito returned to the building the following year to build another installation for Burning Man — three steel figures, which kept her in the defunct factory for three months. Then, in 2007, she returned with plans to build an installation with seven figures genuflecting to a 100-foot replica of an oil derrick, which required her to lease several thousand feet of the building.

At that point, Cusolito began renting the space to other artists to help pay for the lease. By 2009, she’d expanded American Steel Studios to fill two warehouses, covering 6 acres of industrial land.

It became one of the most pivotal artistic hives in a city teeming with such places. Among the hundreds of artists who moved in were welders, trapeze performers, craft brewers, a cello teacher, a holistic doctor, and a gardener tending a compost worm farm.

“It’s not just a bunch of Burners making weird cars,” said Jon Sarriugarte, a blacksmith who helped design the snail car that Oakland Mayor Libby Schaaf has used as a prop in some appearances. He said Kanbar, who is known as a prodigious entrepreneur and patron of the arts, made what may have been his greatest philanthropic gift yet, when he took Cusolito as a tenant.

“By letting Karen rent the place, he unintentionally created this whole incubator,” Sarriugarte said, pointing out that the former steel factory had singularly birthed an arts scene: As its tenants grew their scrappy cottage industries into full-fledged businesses, many of them moved out to open studios of their own.

Support from mayor

With West Oakland becoming a beachhead for new development, city leaders have rallied around the artists who stand to get displaced. Schaaf made a grand statement shortly after she took office, by riding around town in the snail car. She held an inauguration party at American Steel Studios in January, part of a weeklong “Made in Oakland” festival.

Schaaf has tried to intervene on the artists’ behalf, by meeting with Kanbar last year and by approaching another developer to see if he could help find an alternative home for the American Steel tenants.

She said Tuesday that the city has used zoning regulations to help protect its creative class, earmarking certain areas for light industry and manufacturing.

“Preserving industrial artistic uses are part of what I think is the long-term interest of the city,” Schaaf said.

Kanbar declined to comment through his spokesman, Clint Webb, who serves as chief operating officer of KS Properties One.

Webb and Cusolito said they are trying to hammer out a new lease agreement.

‘Whole gamut’ of ideas

Meanwhile, Webb said he gets cold calls every week from people interested in buying the property.

“It’s a whole gamut,” he said. “There’s people who want to turn it into a Chicano Latino cultural center. There are people who want to turn it into a new Oakland Coliseum. There’s the people who think it would be good for biowaste. There are people who wanted to use it as a rainwater runoff collection depot.”

Webb insisted that Kanbar’s overtures had been “casual” and that so far no deals have been brokered.

But at least one developer who eyed the American Steel property said Kanbar is eager to sell, albeit at a steep price.

“He’s got ideas of what he wants to sell it for,” said John Protopappas, head of the Oakland-based real estate company Madison Park Financial. “But we’ll see what the market says.”

Rachel Swan is a San Francisco Chronicle staff writer. E-mail: rswan@sfchronicle.com Twitter: @rachelswan