Gov. John Kasich said Monday that a major South Korean industrial plant builder has joined an effort to build a multibillion-dollar petrochemical plant in eastern Ohio to take advantage of the region’s oil-and-gas boom.

Kasich, a Republican, called the partnership between Seoul-based Daelim Industrial and Thailand’s PTT Global Chemical a “game-changer” for the proposed plant, which has idled in the planning stages for years.

“It’s great to see these two world-class companies coming together to develop an exciting 21st Century industry that would dramatically transform Ohio,” Kasich said in a statement.

Daelim, according to its website, is South Korea’s oldest construction company and an expert in petrochemical technology.

The U.S. subsidiary of PTT has been working for several years with officials from JobsOhio, Ohio’s privatized economic development office, on a proposal to build the plant on the site of a former FirstEnergy coal-fired power plant along the Ohio River in Belmont County.

The facility, commonly referred to as an ethane cracker, would convert ethane, a byproduct of natural gas drilling, into a hydrocarbon called ethylene that’s further processed and used for plastics production and has other industrial uses.

Monday’s announcement again stopped short of a full commitment by either firm to build the plant, but JobsOhio officials said that decision could come by the end of 2018.

The uncertain future of the project has caused concern in an Appalachian region of the state that’s counting on the project to create thousands of construction jobs and hundreds of permanent positions. PTT officials said in February 2017 that the company would decide by the end of that year whether to build the plant. That was after previously saying the announcement would come in the spring of 2017.

PTT has spent more than $100 million on planning work that includes engineering and design, company and JobsOhio officials said.

The new partnership’s plans call for building a plant capable of producing 1.5 million metric tons (1.65 million tons) of ethylene a year, which would be a 50 percent increase in capacity over what PTT originally proposed.

JobsOhio, funded by state liquor proceeds, has spent $19 million toward the effort. Those funds have paid for demolition of the R.E. Burger power plant in an unincorporated area of Belmont County known as Dilles Bottom and the removal of environmental hazards to make the 168-acre (68-hectare) site ready for construction.

PTT is exercising an option to buy an additional 300 acres (121 hectares), which company spokesman Dan Williamson said is further evidence of the partnership’s commitment to the project.