Airgas Inc. (www.airgas.com) will invest $7.5 million in a 42.5-percent increase in capacity at its Star, Miss., plant. The expansion will add 850 tons per day of liquid carbon dioxide capacity to the 2,000-ton-per-day facility and will include an increase in storage capacity at the plant and railcar service from the plant. The expansion is the fourth since the plant opened in 1986. Airgas Carbonic operates eight liquid carbon dioxide plants and is the third largest producer in the United States.