Modern industries ranging from plastics manufacturing to sewage treatment involve massive volumes of potentially toxic chemicals. U.S. production of hazardous and toxic waste rose from 9 million tons in 1970 to 238 million tons in 1990. Potent chemicals, many much more toxic than oil, are everywhere in the world, with new ones constantly being developed. Dispersed and diluted, most of these chemicals do not represent an acute danger. Yet when circumstances allow them to spill into the environment, they can be an immediate and deadly threat to people and wildlife. The most gruesome example of the catastrophic potential for spilled chemicals occurred in Bhopal. Not only was the immediate toxic effect tragic, but Bhopal illustrates the traumatic lingering effects of chemical exposure. Oil poses enduring effects, as well, but seldom as dangerous to people.

Some of the Culprits

The EPA has four characteristics to consider a substance hazardous: whether...