Hearing begins on key case challenging Environment Protection Agency's authority to compel power plants to cut carbon emissions
Barack Obama's authority to compel power plants in the US midwest to reduce the smog and soot that blow across to north-eastern states will be put to the test on Tuesday in the first of three major challenges to environmental regulations.
The supreme court will hear arguments about whether the Environmental Protection Agency (EPA) can set limits on air pollution that, while originating in one state, directly affect the air quality in other states.
It is the first of two cases this session that will help define the limits of the EPA's authority to deal with air pollution and climate change. Early next year, the court will hear a challenge to the EPA's plans to limit greenhouse gas emissions from power plants.
Elsewhere on Tuesday, the federal appeals court will hear a case seeking to overturn EPA limits on mercury and other emissions from coal-fired power plants.
The case was brought by the coal company, Peabody Energy Corp, the United Mineworkers of America, Texas and other states.
In Tuesday's supreme court proceedings, judges will review whether the EPA had the authority to allocate responsibility for air pollution to the different states.
The DC circuit court struck down the regulation in August 2012, following a challenge filed by 15 states.
In Tuesday's proceedings, the EPA and the American Lung Association are expected to argue that the soot particles and ozone generated by coal-fired power plants and other facilities in the midwest are dangerously compromising air quality in north-eastern states.
Soot and smog blown across the country by prevailing westerly winds end up in north-eastern states where they are responsible for tens of thousands of premature deaths every year, and hundreds of thousands of cases of childhood asthma, the EPA argues.
Some states, such as Maryland, Connecticut and Delaware, complain that almost all of their pollution comes from out of state.
The governors of eight of those states petitioned the EPA on Monday to put tighter controls on cross-state pollution.
"Most Americans try to be good neighbours and live by the golden rule," Delaware's governor, Jack Markell, told reporters. "Yet our states are receiving hundreds of thousands of tons of pollution from the states that are upwind of us."
The cross-state air pollution rule facing supreme court review set new limits on nitrogen oxide and sulphur dioxide for 28 states, forcing coal-fired power plants to install new pollution controls, or shut down.
The justices have set aside 90 minutes to hear oral arguments – a sign of the importance they accord to the case. Most cases before the supreme court are allotted 60 minutes for arguments.
Nine states have joined the EPA and the American Lung Association in urging the court to overturn the DC circuit court's ruling. Both the EPA and the lung association, in a telephone conference call with reporters, have talked about the elevated health risks from air pollution, premature deaths from heart disease and lung ailments to developmental problems in infants.
Environmental campaigners are closely watching Tuesday's proceedings. If the judges reverse the lower court ruling it would ease the way for the EPA when next summer it releases new rules on existing power plants' greenhouse gas emissions.