The Enough Project ranked companies based on the steps they have taken to make sure their mobile phones, iPads and other gadgets aren't paying for the weapons used to terrorize Congolese civilians.
The group's advocacy was instrumental in pushing through U.S. legislation that has caused a dramatic decline in the minerals trade from embattled areas of the Congo. However, the reduction in exports hasn't led to a corresponding decrease in violence - eastern Congo is in the grip of a fresh rebellion, and 280,000 people have fled their homes since April.
Congo is home to about 70 percent of the world's supply of tantalum, a metal used in cellphones, according to the U.S. Geological Survey. The vast country also has massive amounts of tin, gold, copper and cobalt.
Although most of the companies had shown improvement since 2010, the Enough Project cited video game console maker Nintendo Co. as trailing behind the rest of the industry when it comes to "conflict minerals."
Armed groups vying for control of these riches have used profits from illegal mining to purchase weapons used in gruesome attacks on civilians. In other cases, they have captured people and forced them to do the digging.
"The exploitation of Congo's mineral resources continues to exacerbate conflict and instability on the ground and consumers are still largely in the dark as to whether or not their products are conflict free," the report said.
The idea that mining exacerbates the Congolese conflict is controversial. Many experts say the real problem in eastern Congo is the lack of a functioning government, not that there are valuable minerals there.
"The minerals trade is a symptom of a deeper problem - that nobody is in charge," said Laura Seay, an assistant professor at Morehouse College in Atlanta who studies the eastern Congo and travels there.
Thursday's report comes just days before a key development is expected on the issue. U.S. legislation passed in July 2010 required American companies using tungsten, tin, tantalum and gold to reveal their supply chains in an effort to avoid using conflict minerals.
However, the law has not been fully implemented yet because the U.S. Securities and Exchange Commission has yet to draft rules on how the law should be applied. The SEC is due to vote on those final regulations next Wednesday.
Even though that law is not yet in effect, the Enough Project said its existence already had helped propel many companies to take action.
The Washington-based group praised Intel Corp. for its pledge to produce a conflict-free microprocessing chip by 2013, becoming the first company to publicly commit to such a deadline.
It also singled out Hewlett-Packard Co. as "the most active corporate participant in a diplomacy work group on Congo."
Apple Inc. was the first company to require its suppliers to use only metals from smelters that have been certified "conflict-free," when enough are available, the Enough Project said.
The group also gave high points to Motorola Solutions Inc., Royal Philips Electronics N.V., Acer Group, Dell Inc. and Microsoft Corp., but described other companies as "laggards."
"Despite growing public awareness about this issue and significant industry movement, Nintendo has made no known effort to trace or audit its supply chain," the report said. "Sharp, HTC, Nikon, and Canon are taking initial steps to join industry efforts, but their progress remains far behind industry leaders."
In a statement released Thursday, Nintendo said it outsources the manufacture and assembly of all Nintendo products and "therefore is not directly involved in the sourcing of raw materials that are ultimately used in our products."
"We nonetheless take our social responsibilities as a global company very seriously and expect our production partners to do the same," the statement said.
The Enough Project said that it wanted the companies to know more about the origins of the minerals they were buying, but not to avoid buying from the country altogether.
"A handful of companies are helping Congo develop a clean trade, but some companies are taking a hands-off approach to instruct their suppliers to not buy minerals from Congo and the region," the group said. "This approach helps cut off armed groups but leaves mining communities in Congo behind."
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