Operations at Shell Polymers Monaca — the first major polyethylene, or plastic, manufacturing complex in the northeastern U.S. — have begun, its operator, Shell Chemical Appalachia LLC, announced Tuesday.

The multibillion-dollar facility on 384 acres in Beaver County, Pa., across the Ohio River from Columbiana County, is designed to produce about 3.5 billion pounds of polyethylene per year. It’s expected to ramp up to full production by the second half of 2023.

The refinery brings in ethane from natural gas wells and chemically “cracks” the liquid fuel by heating it in furnaces to create ethylene, which is used to produce everything from plastics to tires to antifreeze.

A leading gas exploration trade association, the Marcellus Shale Coalition, hailed the opening of the refinery, calling it an “historic day for Pennsylvania.”

The natural gas boom in the vast Marcellus Shale gas reservoir beneath Appalachia attracted Shell to the area. In 2012, the state signed off on a tax break of up to $1.65 billion over 25 years to lure it, and later issued air and water permits to Shell, which began construction in 2017.

The plant looks very similar to a gasoline refinery, with miles of pipes and large storage tanks. The core manufacturing and logistics area covers about 385 acres, with an overall site footprint of about 800 acres. It includes its own power generation and water treatment plants.

Most ethylene production is on the Gulf Coast in Texas and Louisiana. Shell says the location gives it a competitive advantage, with more than 70 percent of the U.S. polyethylene market within 700 miles of Pittsburgh.

The closeness, according to the company, also offers customers shorter supply chains that translate to increased flexibility and access to plastic pellets that can be used in a wide variety of products, from common household goods to consumer and food packaging to industrial and utility products.

Most of its natural gas feedstock is contracted from the nearby Utica and Marcellus shale basins.

“Building this world-class facility is a fantastic achievement and one the team can be proud of; it’s a showcase of Shell’s project delivery expertise,” Huibert Vigeveno, Shell downstream director, said. “With great market access, innovative offers and connected infrastructure, Shell Polymers Monaca is well positioned and ready to serve customers with high-quality, competitive products.”

Shell started main construction at the facility in April 2017 after making the final investment decision in June 2016, according to the company. It needed about 9,500 workers to build at peak construction.

The plant employs about 600 full-time workers and estimates several thousand more spinoff jobs are connected, from private industry and public services needed to support it.