Dow Chemical Co. announced Monday it has successfully restarted its St. Charles Olefins 2 Plant near Hahnville after three years of inactivity.

The plant has been producing ethylene, which is used in alcohol- and plastic-based products, since Dec. 25. Dow said it expects the plant will add $150 million to earnings before interest, depreciation and amortization.

Restarting the plant, which closed in January 2009, is “the first major milestone” in Dow’s Gulf Coast investment strategy, according to Brian Ames, president, Dow olefins, aromatics and alternatives. Dow can reduce the amount of ethylene it buys, lowering its production costs.

Dow’s U.S. strategy involves increasing its competitive advantage by producing more ethylene and propylene at its Gulf Coast plants, which use low-cost natural gas from shale formations as a feedstock.