Senator Elizabeth Warren, D-Mass. suggested foreign-owned crypto mines in the U.S. could pose a threat to the country.

Speaking at a hearing of the Senate Committee on Banking, Housing and Urban Affairs on Thursday, Warren questioned Paul Rosen, Assistant Secretary for Investment Security, Department of the Treasury, on the dangers posed by foreign-owned cryptocurrency mining facilities operating in the U.S.

Warren, a vocal critic of the crypto industry, said crypto mining is a “disaster for the environment,” despite its potential benefits for incentivizing renewables, grid stabilization, stranded energy utilization and job creation. The senator called for strong anti-money laundering protections to prevent such operations from undermining U.S. national security.

“Crypto mines could be …