JobsOhio has invested $20 million in an eastern Ohio site being considered for a massive petrochemical plant.

The state‘s economic development organization said Friday it awarded the grant to Thai chemical company PTT Global Chemical America and its South Korean partner, Daelim Industrial Co.

With this award, JobsOhio has now committed $70 million in grants and loans to the project, according to JobsOhio records.

Economic development officials announced in 2015 that PTT was considering the site along the Ohio River near Shadyside in Belmont County for the project. PTT later brought on Daelim as a partner.

A similar project is being developed by Royal Dutch Shell in western Pennsylvania.

The plant would take ethane, a component of natural gas, and break it down to produce ethylene, which is used in chemical manufacturing. The county is an attractive site because of its proximity to the plentiful, cheap natural gas of the Marcellus and Utica shale formations in Ohio, Pennsylvania and West Virginia.

The plant would be built on the site of FirstEnergy's former R.E. Burger power plant, which closed in 2011.

If the companies proceed, it would be an economic boon for eastern Ohio, employing several thousand workers during construction and several hundred once the plant became operational.

But critics have complained about potential greenhouse emissions from the plant.

The companies said Friday that they anticipate making a final decision on whether to proceed by July.

The $20 million allows site preparation to continue, said Dan Williamson, a spokesman for the companies.

"We are sincerely grateful to JobsOhio,which has been a steadfast and supportive partner without whom this project would not be possible,’’ he said.