Warren stated that most of the mining facilities operating in the United States belong to China and that some facilities are directly linked to the Chinese government. Citing “blockchain analytics farm” data, he noted that nearly a third of mining facilities in the US are owned by Chinese companies.

Warren said such facilities pose potential risks to national security and these risks should be taken seriously. He cited an example of a liquidation order issued by CFIUS (Committee on Foreign Investment) in May 2024. He stated that this order was given to the mining facility called MineOne, which was built in Wyoming and belongs to China.

He emphasized that this facility is located just one mile from Francis E. Warren Air Force Base in Cheyenne. This indicates that the location of the facilities close to strategic military facilities may increase possible security risks.

He noted that in October 2023, a Microsoft data center located near this facility warned that the facility could be a “full-spectrum intelligence gathering operation.” He said such a warning could indicate the possibility that the facility was conducting potential espionage activities.

Warren asked Deputy Secretary Rosen, who runs CFIUS, whether equipment found at crypto mining facilities could be used to “spy” on U.S. military operations and nuclear weapons systems. Rosen acknowledged that such sophisticated equipment could be used for espionage purposes and stated that this was a serious concern for national security.

Warren also noted potential threats to the U.S. power grid from foreign entities. He suggested that these assets could carry out “targeted disruptions and cyberattacks.” He noted that foreign countries, especially Chinese investors, may have the capacity to damage the US energy infrastructure using crypto mining.

Warren stated that some crypto mining facilities were purchased using cryptocurrencies, with the aim of bypassing the traditional banking system and anti-money laundering rules. He claimed that these facilities were “secretly” sending their funds back to China and emphasized that the United States should take legislative steps to solve this problem.

Warren’s latest warning follows her earlier May letter about Iran “financing attacks against Israel” using crypto mining. In this letter, Warren requested details about the revenues generated by Iranian crypto miners and questioned how the United States plans to address this threat.

The Biden government has also launched a crackdown on the crypto mining industry, proposing a 30% tax on miners’ electricity use. This proposal created a huge debate about the future of the industry, with Wyoming Republican Senator Cynthia Lummis arguing that this tax would “destroy” the industry. These criticisms reveal the complexity of policy proposals to strike a balance between crypto mining and energy consumption.