Shelley Malkin, age 10, of Youngstown, Ohio,for her question:

What does DDT stand for?

It's too bad the law did not compel a person to spell out its full name before they spread it around. Suppose DDT had to be sold under its chemical name  ¬dichlorodiphenyl trichloroethane. By the time the purchase was made, the insects it is meant to destroy might be forgotten. Nowadays, more and more regions are banning its use under any name.

The long chemical name for DDT tells us that it is a chlorinated compound of phenyl and ethane. Chemists created a variety of similar chemicals, mostly from the hydrocarbon by products of petroleum. They are cheap to make and for a time they did a fine job of wiping out insect pests. But as we now all know, DDT and its relatives also wiped out countless other creatures and threatened human health. And, after several years, many insects were not bothered by it. But DDT stays around for a long time and tons of it will be polluting the land and sea for many years to come.