A group of Democratic lawmakers led by Senator Elizabeth Warren of Massachuttes has asked six crypto mining companies, including Riot Blockchain, to answer questions about the impact of their operations on the environment and cost of electricity in the US. In separate letters to the chief executives of each firm, the group asks the companies to detail how much electricity they consume, their scaling plans and any agreements they have in place with local utility companies. They have until February 10th to reply.

Lawmakers say they’re concerned about what a dramatic increase in domestic cryptocurrency mining has meant for the environment and consumers. Specifically, they cite a 2021 study from the University of California, Berkeley that estimated crypto mining in upstate New York raised annual electricity bills by approximately $165 million for small businesses and $79 million for consumers, “with little or no local economic benefit.” They also point to the fact that energy consumption related to Bitcoin mining tripled between 2019 and 2021.

“The extraordinarily high energy usage and carbon emissions associated with Bitcoin mining could undermine our hard work to tackle the climate crisis – not to mention the harmful impacts crypto mining has on local environments and electricity prices,” Senator Warren said. “We need more information on the operations of these crypto mining companies to understand the full scope of the consequences for our environment and local communities.”

The group stops short of suggesting regulatory action could be on the horizon for the industry, but clearly the effect of cryptocurrency on other parts of the economy is something lawmakers are thinking about. On January 20th, the House Energy and Commerce Committee held a hearing titled “Cleaning up Cryptocurrency: The Energy Impacts of Blockchains.” What’s more, US lawmakers have taken a more board interest in cryptocurrencies in recent months. That was on display in December when the Senate held a hearing on Stablecoins.