The high-end, high-tech industry that produces computers and cell phones has a dirty little secret: toxic waste. Phones and computers contain dangerous metals like lead, cadmium and mercury, which contaminate the air and water when those products are dumped.

Electronic waste, or e-waste, amounts to 20 million to 50 million tons a year worldwide. The United States is the world's top producer of e-waste, but sends much of it over to developing nations like China, India and Nigeria.

In the cities like the southern Chinese town of Guiyu, the poor strip the waste dumps with little protection, melting down components and breathing in poisonous fumes. What can't be recycled is simply dumped, turning already poisoned rivers into toxic sludge.

The Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal was established in 1989 to control the hazardous garbage flowing from rich countries to poor ones. But the United States never signed onto the treaty and some of the destination nations, such as China, allow the dumping to continue for the money it brings in.