March 5 (Reuters) - A federal appeals court on Tuesday

refused to hold five major technology companies liable over

their alleged support for the use of child labor in cobalt

mining operations in the Democratic Republic of the Congo.

In a 3-0 decision, the U.S. Court of Appeals for the

District of Columbia ruled in favor of Google parent Alphabet

, Apple ( AAPL ), Dell Technologies ( DELL ), Microsoft ( MSFT )

and Tesla, rejecting an appeal by former child

miners and their representatives.

The plaintiffs accused the five companies of joining

suppliers in a "forced labor" venture by purchasing cobalt,

which is used to make lithium-ion batteries that are widely used

in electronics. Nearly two-thirds of the world's cobalt comes

from the DRC.

According to the complaint, the companies "deliberately

obscured" their dependence on child labor, including many

children pressured into work by hunger and extreme poverty, to

ensure their growing need for the metal would be met.

The 16 plaintiffs included representatives of five children

who were killed in cobalt mining operations.

But the appeals court said buying cobalt in the global

supply chain did not amount to "participation in a venture"

under a federal law protecting children and other victims of

human trafficking and forced labor.

Circuit Judge Neomi Rao said the plaintiffs had legal

standing to seek damages, but did not show the five companies

had anything more than a buyer-seller relationship with

suppliers, or had power to stop the use of child labor.

She added that many other parties are responsible for labor

trafficking, including labor brokers, other cobalt consumers and

the DRC government.

"Without more specific allegations, the question is whether

the tech companies' purchasing an unspecified amount of cobalt

from a supply chain originating in DRC mines plausibly

demonstrates 'participation in a venture' with anyone engaged in

forced labor in that supply chain," Rao wrote. "We hold that it

does not."

Terry Collingsworth, a lawyer for the plaintiffs, in an

email said his clients may appeal further, and could file new

lawsuits if the companies' conduct met the court's test.

The decision provides "a strong incentive to avoid any

transparency with their suppliers, even as they promise the

public they have 'zero tolerance' policies against child labor,"

he said. "We are far from finished seeking accountability."

Google had no immediate comment. Apple ( AAPL ), Dell, Microsoft ( MSFT ),

Tesla and their respective lawyers did not immediately respond

to requests for comment.

Tuesday's decision upheld a November 2021 dismissal by U.S.

District Judge Carl Nichols in Washington.

The cobalt suppliers included Eurasian Resources Group,

Glencore ( GLCNF ), Umicore and Zhejiang Huayou Cobalt

, court papers show. None was named as a defendant.

The case is Doe 1 et al v Apple Inc ( AAPL ) et al, D.C. Circuit

Court of Appeals, No. 21-7135.