ALIQUIPPA — A plan to build a huge petrochemical plant in Western Pennsylvania is making progress, Shell Oil Co. officials said Wednesday — but there's still no guarantee the multi-billion dollar project will actually be constructed.

That message of optimism and caution was stressed by company officials to about 200 people who showed up for the first of two public meetings regarding a proposed plant site about 30 miles northwest of Pittsburgh.

Shell has an option to purchase a 300-acre industrial site on the Ohio River and demolition of a zinc factory that was there has already begun. But Shell general manager Dan Carlson said that doesn't necessarily mean the so-called ethane cracker plant will be built. In some other states — Colorado, for example — Shell invested tens of millions of dollars in proposed projects before deciding to shut them down.

Carlson said the company has signed long-term contracts with about 10 energy companies to supply the proposed plant.