A human rights group has said that Nintendo, HTC and Sharp are among companies that don't do enough to ensure conflict minerals do not end up in their products.
The Enough Project, a part of the Centre for American Progress, put Nintendo at the bottom of its conflict minerals ranking in a report on sourcing minerals that are mined in war conditions amid human rights abuses.
"Nintendo has made no known effort to trace or audit its supply chain," the report stated baldly.
The Project also singled out Sharp, HTC, Nikon and Canon, saying that although they had started to look at conflict minerals, their progress was "far behind industry leaders".
The report scores firms on their efforts to figure out where the minerals and metals they use in their tech comes from and their attempts to get a conflict-free certification, as well as environmental rankings and support for legislation against conflict minerals.
Intel, Motorola, HP and Apple were all at the top of the list, having "moved forward to develop solutions despite delays in the legislative rule-making process by the US Securities and Exchange Commission - an excuse that many other companies have used to explain their lack of significant action", the Project said.
The report refers to the US 2010 Dodd-Frank financial reform law, which would require companies to disclose whether they use tantalum, tin, gold or tungsten from the Democratic Republic of Congo. The SEC is due to vote on 22 August on the guidelines needed to enforce the law.
Conflict diamonds from the DRC are a well-known commodity, but the large reserves of the minerals used in electronics that are in the country haven't had as much press.
With the new rules, firms will have to identify if there are any of conflict minerals in their products and if they are, the company will have to do a due diligence check to track them back to their origins. ®