For a good example of the law of unintended consequences, look no further than the nationwide push to promote ethanol. Ten years ago, federal officials became concerned that a common gasoline additive called MTBE, which reduces air pollution, turned out to be a carcinogen, causing major water pollution problems.
The Environmental Protection Agency recommended phasing out MTBE, so many states ordered refineries to switch to ethanol. Meanwhile, Congress in 2005 mandated an increase in using renewable fuels such as ethanol. Now each gallon of gas sold in Florida contains up to 10 percent ethanol.
Because most ethanol is made from corn, the increased demand spurred Midwestern farmers to increase their corn production. That led to an increased demand for fertilizer.
Most fertilizer in the United States comes from phosphate mined in Florida and shipped through the Port of Tampa. The ethanol boom led to big profits for phosphate companies that run mines near Tampa.
But more fertilizer led to more nitrogen and phosphorus polluting the runoff flowing into the Mississippi River. They boosted an area in the Gulf of Mexico called "the dead zone."
The dead zone, which appears every summer, is an area where the water lacks oxygen. Nothing can live there. First mapped in 1985, the dead zone has grown steadily. Last year it was nearly as big as New Jersey. As it has grown, the gulf's fishing industry has shrunk.
Last year the EPA issued a plan that talked about reducing the dead zone, but the plan "contained very few actions with time lines attached," said Matt Rota of the Gulf Restoration Network.
A month ago, an arm of the National Academies of Science issued a report blasting the EPA and the U.S. Department of Agriculture for failing to deal with the problem more quickly, "given that it will require years, if not decades," to start seeing results.