Nearly 10% of the U.S. corn crop is treated with aldrin, a highly effective pesticide. Both the manufacturer, Shell Chemical, and the Department of Agriculture consider the substance essential to control insect damage in the Midwest corn belt. Recently, after a year of still-unfinished hearings, the Environmental Protection Agency announced that it plans to order a halt in the production of aldrin and a related Shell pesticide, dieldrin. Reason: the chemicals present "extremely high cancer risk."
After it is applied, aldrin gradually breaks down into dieldrin, a durable chlorinated hydrocarbon; the pesticide is long-lasting and requires only one application per year. That...