Folks in Orrington are getting ready to go to the polls to vote on a clean-up plan, endorsed by town selectmen, for the former HoltraChem plant.Dozens of people attended a public hearing last night to talk about the efforts to remove mercury and other pollutants from the property. In February, town selectmen voted to support a quicker clean up, proposed by the company that owns the property. Mallinckrodt officials say that could cost about $100 million in the next five years. But the Department of Environmental Protection is considering a more extensive plan at a cost of $250 million.Residents upset with the selectmen’s decision started a petition drive, which prompted to town vote. It’s set for April 23rd. Town Manager Paul White says the DEP may host another informational meeting before that vote.