And though US states increasingly require that electronics be sent to collection and recycling centers, even from those centers US firms can send the e-waste abroad legally because the US Congress has not ratified the Basel Convention.
The results are visible on the streets of Guiyu, where the e-waste industry employs an estimated 150,000 people. Shipping containers of computer parts, old video games, computer screens, cellphones and electronics of all kinds, from ancient to nearly new, are dumped onto the streets and sorted for dismantling and melting.
Valuable metals such as copper, gold and silver are removed through melting and acid baths, while steel is torn out for scrap and plastic is ground into pellets for other use.
This is big business for those who control the trade. Luxury sedans are parked in front of elaborate mansions in downtown Guiyu, adorned with fancy names such as "Hall of Southernly Peace."
Many of those who do the dirty work are migrants from poorer parts of China, either too desperate or too uninformed to care about the health risks.
In the town of Nanyang, a few minutes drive from Guiyu, a middle-aged couple from Hunan Province sorts wiring in a mud-floored shack. Such work, including melting down motherboards, earns them about 800 yuan (US$100) per month, said the husband, who answered reluctantly and wouldn't give his name.
Many houses double as smelter and home. Gas burners shaped like blacksmith's forges squat beside the front doors, their flues rising several stories to try to dissipate the toxic smoke.
Nonetheless, a visitor soon develops a throbbing headache and metallic taste in the mouth. The groundwater has long been too polluted for human consumption. The amount of lead in the river sediment is double European safety levels, according to the Basel Action Network, an environmental group.
Yet, aside from trucking in drinking water, the health risks seem largely ignored. Fish are still raised in local ponds, and piles of ash and plastic waste sit beside rice paddies and dikes holding in the area's main Lianjiang river.
Chemicals, including mercury, fluorine, barium, chromium and cobalt, that either leach from the waste or are used in processing, are blamed for skin rashes and respiratory problems. Contamination can take decades to dissipate, experts say, and long-term health effects can include kidney and nervous system damage, weakening of the immune system and cancer.
"Of course, recycling is more environmentally sound," said Wu Song, a former university student who has studied the area. "But I wouldn't really call what's happening here recycling."
Those who control the business in Guiyu are hostile to outside scrutiny. Reporters visiting the area with a Greenpeace volunteer were trailed by tough-looking youths who notified local police, leading to a six-hour detention for questioning.
Government departments from the provincial to township levels refused to answer questions. The central government's Environmental Protection Agency did not reply to faxed questions.
Guiyu faces growing competition from other cities, notably Taizhou, about 725km up the coast in Zhejiang Province.
Meanwhile, collection yards have sprung up on the fringes of most major cities. The owners sell what they can to recyclers -- most of them unregulated -- and simply dump the rest.