Indeed, the quantity of PCBs still in use plus the quantity still languishing in waste dumps exceeds the total amount that has already escaped into the general environment. Without a program to recall and contain them, semivolatile PCBs will continue to insinuate themselves into the food chain for decades.

Here in the United States, a study of nearly 700 women in California showed an increased risk of fetal death among babies whose mothers lived near crops when certain pesticides were sprayed. The largest risks were found among pregnant women exposed during the critical first trimester and among those who lived in the same square mile where pesticides were used.

The study of how substances alter gene expression is part of the field of epigenetics. Some chemical exposures appear to turn on and turn off genes in ways that disregulate cell growth and predispose for cancer. From this perspective, our genes are less the command-and-control masters of our cells and more like the keys of piano, with the environment as the hands of the pianist.

We can decide that the presence of cancer-causing substances in our air, water, and food is too expensive. A 2009 study, for example, has found that coal miners in Appalachia costs the region five times more in premature deaths, including from cancer, than it provides to the region in jobs, taxes, and economic benefits. In California, the production and use of hazardous chemicals cost the state $2.6 billion in 2004 alone in lost wages and health-care expenses to treat workers and children with pollution-linked diseases.

Indeed, the quantity of PCBs still in use plus the quantity still languishing in waste dumps exceeds the total amount that has already escaped into the general environment. Without a program to recall and contain them, semivolatile PCBs will continue to insinuate themselves into the food chain for decades.

From the right to know and the duty to inquire flows the obligation to act.

By 1990, the EPA had tallied up 32,645 sites of past chemical waste dumping in need of cleanup. Some of these are actual waste landfills, but many are former manufacturing sites where drums full of chemicals have been simply abandoned. The names of the most notorious appear on the EPS's National Priorities List. These are the so-called Superfund sites, names for the super fund of money put together by Congress in 1980 to clean them up. In 2009, the Superfund list contained 1,331 sites.