Up to three-quarters of the computers and other electronic equipment being sent to African countries under re-use and repair programmes are effectively waste, according to the Basel Action Network.
The environmental organisation seeks to ban the export of toxic waste to third-world countries.
Used electronic equipment is increasingly being exported as efforts to bridge the digital divide get under way. But the trade is also fostered by strict recycling and disposal laws in Europe and the US.
Exporting the goods provides a loophole to circumvent expensive recycling programmes.
Computers contain many toxic materials including heavy metals and flame retardants.
Western nations have beefed up environmental legislation in recent years, requiring users to dispose of used electronic equipment at recycling stations.
But organisations are using the export of old equipment as a way to circumvent such legislation, the Basel Action Network alleged.
"Re-use is a good thing and bridging the digital divide is a good thing, but exporting loads of techno-trash in the name of these lofty ideals, and seriously damaging the environment and health of poor communities, is criminal," said Jim Puckett, a coordinator for the group.
The organisation claims to have tracked computers found in Lagos back to schools and government agencies. The trade is illegal under the international Basel Convention.
Analyst firm Gartner said in a September study that the demand for used computers is not met by supply. But the firm also noted that only 36 per cent of the 152 million second-hand PCs shipped in 2004 actually ended up being used.
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