In Phase I, half the total reductions were required by January 1, 1995, largely by requiring 110 electric power generating plants (261 units in 21 states) to cut sulfur dioxide emission rates to 2.5 pounds per million British thermal units (3.9 kg/MWh). Each of these generating units was identified by name and location, and a quantity of emissions allowances was specified in the statute in tons of allowable SO2 emissions per year.[7]