Is mercury a local problem or not? For years, power plant operators have claimed that mercury deposition is really a global problem. Environmentalists have pointed to studies arguing that hot spots affected by local emissions do exist. This week, according to the Cape Cod Times, John Colman, a USGS researcher – hardly likely to be a shill for the power industry – is going to report results of a study showing that mercury accumulation in both soil samples and fish tissue are comparable in Cape Cod and the Olympic Peninsula in Washington. Given prevailing wind directions, it’s hard to find a local source for mercury on the Olympic Peninsula.

According to the Cape Cod Times, Mr. Colman said that "the idea that burning coal is screwing up fish all over the Northern Hemisphere is kind of terrifying.” And I’ll bet that the United States power generation industry finds it terrifying that it may have to make very substantial – and costly – reductions in mercury emissions even though US emissions are about 5% of the world total and may not have a significant impact on the US environment.

I’m not discounting the need for regulation in the United States. Mercury is a real toxin. However, it would also be wrong to ignore the global aspect. To regulate the US power generation industry because doing so will solve a significant public health and environmental problem is one matter. To regulate the US power generation industry because we have to send a signal to the world that we are willing to regulate ourselves in order to persuade China to control mercury from its own coal-fired power plants is another. When the state of our nation is such that businesses are looking to put “China-Free” labels on their products, it will not be easy to persuade a significant segment of the population to support costly mercury controls when there is evidence that a substantial part of the problem stems from cheap coal-fired energy in China that delivers a twofer – allowing China to make goods more cheaply, while exporting its mercury pollution downwind to the United States.