Five quarts of oil can lubricate a car engine for five thou- sand miles against friction and heat, forces that would otherwise destroy an unprotected engine in a trip to the grocery store. The same quantity, barely more than a gallon, can also contaminate 750,000 gallons of water, more than all the water used in a year by two average American families. If that one gallon of oil were multiplied by 68 million, the size of the massive Amoco Cadiz oil tanker spill that occurred off the French coast in 1978, the power of oil to cause havoc begins to take focus. It is simply mind-boggling.

Far more potent than oil, a thimble-full of pure liquid chlorine can disinfect hundreds of thousands of gallons of drinking water, killing deadly germs that could sicken hundreds of people. Yet if that chlorine were spilled into a crowded room, it...