The first manufacturing plant in the Pullman neighborhood in 30 years celebrated its opening on Tuesday, marking a midway point in developing retail, restaurants and potentially another industrial plant on a former Ryerson steel mill brownfield, officials say.

The grand opening, complete with colorful balloons, celebratory music and cheering employees, showed off the “South Side Soapbox” — the nickname for the sole North American factory owned by Method Products. Method is a San Francisco-based company that generates $100 million in yearly revenues making soap and other environmentally friendly household products.

The $33 million factory, located on 22 acres at 720 E. 111th St., just east of the Bishop Ford Expressway, boasts what company officials say is the world’s biggest rooftop greenhouse.

The greenhouse, covering 75,000 square feet, will produce more than 1 million pounds of fresh and pesticide-free produce each year for local retailers and restaurateurs.

The irony wasn’t lost that the Pullman neighborhood, which President Barack Obama on Feb. 19 designated a national monument, is considered a food desert because of residents’ lack of easy access to fresh foods, grocery stores and healthy food sources.

“Here we have a hydroponic farm in a food desert,” said Jonathan Bond, chairman of the board of Method Products, referring to the greenhouse’s method of growing plants in water without soil. The greenhouse is run by Brooklyn-based Gotham Greens, while the plant’s bottle production is run by Amcor Rigid Plastics, a Melbourne, Australia-based company.

The plant also features skylights, three solar panels, a 230-foot wind turbine that supplies 30 percent of the facility’s energy and a 120-gallon solar-powered heating system.

Ald. Anthony Beale (9th) said the plant “is just the beginning” of development at the site. He credited a drop in crime in his ward to the increase in available jobs.

The plant, which gives “fun” titles to its workers and executives, will employ 70 “movers and makers” — the front-line employees who manufacture and distribute the products, said Sha’Rhonda Neil, Method’s human resource manager whose fun title is personnel doctor.

Of the 62 employees hired so far, 32 percent live in the 60628 ZIP code that includes the Pullman, West Pullman and Roseland neighborhoods.

Neil, who grew up in the Chatham neighborhood, said the plant is still hiring IT support staff and maintenance managers who have an engineering background.

Neil said the plant opening “means a lot to me.”

“To bring this type of facility to the South Side has made a big impact on my life,” she said. “I’m excited about it.”

The site, which received $8.1 million in tax-increment-financing money for cleanup and $1 million in city funds for worker training programs, has another 30 acres of land just north of the plant zoned for industrial use.

David Doig, president of the not-for-profit community development corporation Chicago Neighborhood Initiatives, said Tuesday that negotiations are underway to bring a food-processing company to that property. Chicago Neighborhood Initiatives owns the undeveloped property in partnership with U.S. Bank.

Across the street from the Method plant on 111th Street, final touches are being put on a strip mall development that would include restaurants, a dry cleaner and small retailers, said Doig.

Beale said the Pullman property, which includes a Wal-Mart store, Ross Stores, Dollar Tree, Planet Fitness, City Sports and Villa Shoes, was among 150 sites in four states that Method Products reviewed.

Adam Lowry, co-founder, chief greenskeeper and chief global sustainability officer at Method, said the company chose the Pullman site because local residents lobbied so hard for it.

“The people have not only a great work ethic, but great pride in trying to revitalize their community,” he said. “The people came out and said, ‘We want to work with you to do something great in this neighborhood.’ ”