Senator Sheldon Whitehouse (D-RI), the ranking member of the Senate Committee on Environment and Public Works, sent a letter to Meta CEO Mark Zuckerberg on Wednesday questioning how much energy the data center will require and the corresponding greenhouse gas emissions it will produce. The letter highlights that relying on gas to power the data center contradicts Meta’s environmental pledges.

As tech companies race to expand data centers for training and deploying new AI tools, there is a surge in electricity demand. In this instance, Entergy, the power utility, aims to fulfill this demand with new gas infrastructure, sparking concerns about the potential negative effects on both the environment and local communities from Meta’s data center.

“Meta’s backslide from its own climate pledges risks triggering broader economic harm at a time when we urgently need corporate responsibility,” Sen. Whitehouse said in a statement emailed to The Verge.

In 2020, Meta pledged to reach net-zero emissions across its operations, supply chain, and consumer use of its products by the end of the decade. But the company’s carbon footprint is larger now than it was when it set that goal, according to its latest sustainability report, as it doubles down on AI.

The company has tried to reduce its emissions by matching its electricity use with equal purchases of renewable energy. It’s a strategy Meta and other big companies often take: pay to support new clean energy projects to try to cancel out the environmental effects of your facilities plugging into a power grid that runs on dirty energy. Environmental advocates are increasingly concerned that this strategy still burdens communities with local pollution, and that the pressure to meet rising electricity demand from AI is boosting fossil fuel use rather than renewable energy.

We’re seeing that tussle play out in Richland Parish, Louisiana, where Meta has plans to build its largest data center to date. It’s spending $10 billion on the project, the company announced in December. Once complete, the campus would span 4 million square feet, about as large as 70 football fields. But the project is moot unless Meta can ensure there will be enough electricity available for all those servers, a problem it’s working with Entergy to solve. Entergy proposed building three entirely new gas plants with a total capacity of 2,260 megawatts to support the data center, but it has to get regulatory approval first.

Some advocates contend that there hasn’t been enough transparency around Meta’s data center plans to help the public understand the potential impact on the local power grid. The New Orleans-based Alliance for Affordable Energy and the Union of Concerned Scientists filed a motion in March asking the Louisiana Public Service Commission to add Meta as an official party to proceedings over whether to approve construction of the new gas plants. Doing so would compel the company to disclose more information, and the commission is scheduled to consider the motion on Monday.

“It’s hard to wrap your brain around [whether] a facility like this either might be good for your community or bad for your community without understanding the possible impact to your electrical system, your bills, and your water,” says Logan Burke, executive director of the Alliance for Affordable Energy.

There are already forecasts that rapidly growing data center electricity demand could raise electricity bills in the US. Meta said in December that it would contribute $1 million a year to an Entergy program that helps older adults and people with disabilities afford their bills. Data centers have also been notorious water-guzzlers, although Meta says it would invest in projects to restore more water than it would consume.

Sen. Whitehouse’s letter, meanwhile, asks Meta to answer a list of questions by May 28th. On top of questions about the data center’s electricity use and greenhouse gas emissions, Whitehouse wants to know what the justification is for building gas-fired power plants rather than renewable energy alternatives. And it presses Meta to explain how the proposal aligns with its 2030 climate goal.

Meta maintains that it’ll continue matching its electricity use with support for renewable energy, including a commitment to help fund 1,500 megawatts of new solar and battery resources in Louisiana. It also said it would help fund the cost of adding technology to at least one power plant that would capture carbon dioxide emissions. Whitehouse wants to know how much funding it will provide and how much carbon will be captured. Carbon capture tech has been prohibitively expensive to deploy and costs are often offset by using the captured CO2 to produce more fossil fuels through a process called enhanced oil recovery.

“We received the letter and look forward to providing a response,” Meta spokesperson Ashley Settle said in an email to The Verge. “We believe a diverse set of energy solutions are necessary to power our AI ambitions – and we continue to explore innovative technology solutions.”

Entergy didn’t immediately respond to inquiries from The Verge. It has a goal of making sure that 50 percent of its generating capacity is carbon pollution-free by 2030. But the utility said that gas “is the lowest reasonable cost option available that can support the 24/7 electrical demands of a large data center like Meta,” in a statement to Fast Company, which first reported on Whitehouse’s letter.