Major electronics firms - including Apple, HP, Samsung, Microsoft and Lenovo - are failing to check that cobalt mined by child labourers has not been used in their products, says Amnesty International in a report published today.

The report traces the sale of cobalt, used in lithium-ion batteries in phones, laptops and tablets, from mines in central Africa where it says children as young as seven and adults work in dangerous conditions.

"The glamourous shop displays and marketing of state of the art technologies are a stark contrast to the children carrying bags of rocks, and miners in narrow man-made tunnels risking permanent lung damage," said Mark Dummett, business and human rights researcher at Amnesty International upon the publication of the report, This is what we die for: Human rights abuses in the Democratic Republic of the Congo power the global trade in cobalt.

"Millions of people enjoy the benefits of new technologies but rarely ask how they are made. It is high time the big brands took some responsibility for the mining of the raw materials that make their lucrative products."

The report, prepared by Amnesty in conjunction with Afrewatch, documents how traders buy cobalt from the former province of Katanga in the Democratic Republic of Congo, where child labour has been shown to be rife. The report charts how this cobalt is then sold to Congo Dongfang Mining (CDM), a wholly-owned subsidiary of Chinese mineral giant Zhejiang Huayou Cobalt Ltd (Huayou Cobalt).

Amnesty International's investigation used investor documents to show how Huayou Cobalt and its subsidiary CDM process the cobalt before selling it to three battery component manufacturers in China and South Korea. In turn, they sell to battery makers who claim to supply technology companies, including Apple, HP, Lenovo, Microsoft, Samsung and Sony.

Amnesty International contacted the 16 multinationals who were listed as direct or indirect customers of the battery manufacturers that are documented as sourcing processed ore from Huayou Cobalt.

While some of the multinationals denied sourcing from Huayou Cobalt and others from the DRC, Amnesty says that none provided enough details to independently verify where the cobalt in their products came from.

"It is a major paradox of the digital era that some of the world's richest, most innovative companies are able to market incredibly sophisticated devices without being required to show where they source raw materials for their components," said Emmanuel Umpula, Afrewatch (Africa Resources Watch) executive director.

"The abuses in mines remain out of sight and out of mind because in today's global marketplace consumers have no idea about the conditions at the mine, factory, and assembly line. We found that traders are buying cobalt without asking questions about how and where it was mined."

Child labor and deadly mines

Amnesty International researchers found that the vast majority of miners work long hours every day without basic protective equipment, such as gloves, work clothes or facemasks to protect them from lung or skin damage.

Children told Amnesty International they worked for up to 12 hours a day in the mines, carrying heavy loads to earn between one and two dollars. In 2014, about 40,000 children worked in mines across southern DRC, many of them mining cobalt, according to UNICEF.

Paul, a 14-year-old orphan, started mining at the age of 12. He told researchers he had been made ill by spending so much time underground.

"I would spend 24 hours down in the tunnels. I arrived in the morning and would leave the following morning ... I had to relieve myself down in the tunnels ... My foster mother planned to send me to school, but my foster father was against it, he exploited me by making me work in the mine."

Today there is no regulation of the global cobalt market, unlike other metals and ores used in electronic and other consumer goods. Cobalt does not fall under existing "conflict minerals" rules in the US, which cover gold, coltan/tantalum, tin and tungsten mined in DRC.

What the tech giants say

Amnesty International says that none of the companies named had been in touch with Huayou Cobalt or traced where the cobalt in their products had come from prior to being contacted.

All of the named companies say they have "zero tolerance policies" on child labor but Amnestry International's Dummett said: "this promise is not worth the paper it is written [on] when the companies are not investigating their suppliers".

Apple does not deny the link between its products and Huayou, saying that it is "evaluating dozens of different materials, including cobalt, in order to identify labor and environmental risks as well as opportunities for Apple to bring about effective, scalable and sustainable change".

"As we gain a better understanding of the challenges associated with cobalt we believe our work in the African Great Lakes region and Indonesia will serve as important guides for creating lasting solutions".

Both Samsung and its supplier Samsung SDI say they do not source cobalt-derived battery parts from CDM or Huayou Cobalt - directly or indirectly. Samsung SDI does say, however, that "it is impossible for us to determine whether the cobalt supplied to Samsung SDI comes from DRC Katanga's mine".

Microsoft said it couldn't guarantee that none of the cobalt used in its products could be sourced back to the former Katanga province of DRC "due to our supply chain complexity".

It said that it did source batteries from a supplier that Amnesty says buys cobalt from CDM and Huayou but that this was a "very limited number of batteries for a product development project". It adds that "to our knowledge", these batteries are "not used in any product currently sold by Microsoft".

HP says it had started an investigation with its suppliers but "as of now we have not found any linkage between our products and the DRC mine". Similarly Sony says it has launched an investigation, which also "so far" has not yielded any "obvious" signs that Sony products contain cobalt originating from Katanga in the DRC".

Lenovo said it had identified two "third-party trademark licensees" that make products sold under the Motorola brand that source batteries from a supplier Amnesty has linked to CDM and Huayou. Lenovo says if an internal investigation verifies Amnesty's concerns then it will order the licensee to stop using the supplier until it can "demonstrate compliance to Lenovo's requirements".

Amnesty International and Afrewatch conclude the report by calling on multinational companies who use lithium-ion batteries in their products to conduct human rights due diligence, investigate whether the cobalt is extracted under hazardous conditions or with child labour, and be more transparent about their suppliers.