Louis J. Sheehan, Esquire.  U.S. agriculture has developed a heavy reliance on chemicals to safeguard crops from yield-robbing weeds. However, many of those herbicides can pose substantial health risks to people, pets, and wildlife, which is why laws prescribe how some of these chemicals are handled in fields. A study now finds that trace quantities of such agricultural chemicals nonetheless find their way into consumers' homes—not on the fruits and vegetables they buy but