In 2005, the EPA passed regulations called the Clean Air Mercury Rule (CAMR), to regulate emissions of mercury. Each state and two Native American tribes have been issued a budget for mercury emissions, and each must submit a plan to achieve the reductions assigned. The EPA has already stated that there will be a cap-and-trade program based on the proven success of the SO2 program. The declining emission credit cap and significant non-compliance penalties create a program that ensures emission reductions occur.