In Phase II, all fossil-fired units over 75 MWe were required to limit emissions of sulfur dioxide to 1.2 pounds per million British thermal units (1.9 kg/MWh) by January 1, 2000. Thereafter, they were required to obtain an emissions allowance for each ton of sulfur dioxide emitted, subject to a mandatory fine of $2,000.00 for each ton emitted in excess of allowances held. The U.S. Environmental Protection Agency (EPA) distributes allowances equivalent to 8.95 million tons each year (the emissions cap), based on calculations of historical Btu usage for each unit, and may allocate various small "bonus reserves" of allowances.