 As a by-product, the facility produced 60,000–70,000 tons of slag per year.Twice per year – for four weeks in the spring and two weeks in the fall – the plant shut down to transport the slag.Prior to its closure, the annual emissions of the facility - when all units were operational - was 10,629 tons of nitrogen oxides (NOx), 40,370 tons of Sulfur dioxide (), and 4,410 tons of particulates smaller than 10 micrometers.