UNDER CONSTRUCTION — Royal Dutch Shell’s cracker plant is under construction in Potter Township, Beaver County. -- Celeste Van Kirk

MONACA, Pa. — Cranes are not an endangered species at the petrochemical ethane cracker plant under construction in Beaver County.

Dozens of construction cranes tower above the landscape in Potter Township. Located near the Ohio River, the equipment is easily seen by motorists passing overhead on Interstate 376.

This is where Royal Dutch Shell is building the first U.S. cracker operation outside of the Gulf of Mexico in more than 20 years.

For nearly a year now, the $6 billion project has been a 340-acre beehive of activity. It will continue to be so until the facility is fully operational, which is targeted to be in the early 2020s.

There are more than 3,700 construction workers on the site, and that will hit a peak of about 6,000 later this year, said Michael Mann, spokesman for Shell. Trades workers from throughout the region are busy at the site.

Once completed, the buzz at the beehive will be even more palpable. This promises to be a monstrous complex, consisting of the cracker; three units that will convert ethylene into polyethylene pellets; a natural gas-fired power plant; a loading dock; and a wastewater treatment plant.

Mann said work is under way on a number of the largest structures.

Manufacturing of plastics is expected to be a major outcome of the operation. A cracker plant “cracks” ethane molecules into petrochemical building blocks that can be refined to create polyethylene, a plastic used for various purposes, from food packaging to automotive parts.

Ethane, propane and butane are natural gas liquids found in some natural gas products in the Marcellus and Utica shales, which run through this region. Interstate 79 is generally regarded as the demarcation line between wet gas (west of I-79) and dry (east). Ethane mainly comes from wet gas.

Locally, natural gas deposits in Marshall and Wetzel counties in West Virginia are filled with wet gas, as are many wells producing in Belmont County.

Getting to the construction phase in Monaca has been a long, circuitous route for Shell. The company first discussed construction of a cracker in the Tri-State Area in mid-2012. Four years of talks, studies and general due diligence followed, and led to a corporate decision in 2016 to follow through.

Shell would build on property that Horsehead, a zinc smelting company, operated for years, and which required plenty of environmental remediation.

That, a rerouting of state Route 18, permitting and licensing resolutions, and other issues took two years before work on the cracker plant itself could begin.

Now it’s happening.

This is a groundbreaking project for the Tri-State Area, but one that may lead others to break ground for similar plants. There has been talk of developing a petrochemical hub in the region, as a cracker proposed for Dilles Bottom in Belmont County has cleared virtually all hurdles — except getting the final go-ahead from investors.

A second cracker along the Ohio River then could, eventually, lead to a third. But first, there’s the first one, the one with all those cranes.