Hillary Clinton is growing cozier with the hydraulic fracturing industry, just months after she promised to heavily regulate it.

The Democratic Party’s presidential candidate attended a $50,000 per place fundraiser in Aspen, Colorado on Tuesday, hosted by fracking magnate Charif Souaki. The event raised $650,000 for the campaign.

As the International Business Times reported, Souaki “amassed his fortune working for natural gas companies including one he founded last year, Tellurian Investments.” A subsidiary of Tellurian, Driftwood LNG, filed for a license in June with the Federal Energy Regulatory Commission (FERC) to construct a natural gas export facility in Louisiana.

Hydraulic fracturing — or fracking — refers to a process by which energy, primarily natural gas, is extracted. It involves shooting millions of gallons of water and chemicals into underground shale rock formations, which releases hydrocarbons trapped inside.

Fracking is heavily scrutinized due to concerns about the slurry of chemicals used in the process. The injection of the industrial mixtures into the earth may be contaminating nearby drinking water sources, critics say. Congress passed legislation in 2005 that shields the industry from having to report on the contents of their fracking fluids.

The splitting of rock deep underground has also resulted in increased seismic activity for those living around fracking wells. A study published in May by researchers at the University of Texas concluded that hydraulic fracturing is now the leading cause of earthquakes in the state.

Fracking is also known to release large quantities of methane, which is a potent greenhouse gas and significant contributor to global warming.

During the Democratic primary against Sen. Bernie Sanders (I-Vt.) — a staunch opponent of fracking — Clinton tried to downplay her support for the controversial energy extraction technique in hopes of appealing to the greener electorate.

In a March debate in Flint, Michigan, Clinton laid out a number of new conditions that fracking companies would have to comply with in order to stay in business. They included: the need for local support; the capture of methane and the prevention of water contamination, and the disclosure of chemicals used in the process.

“By the time we get through all of my conditions, I do not think there will be many places in America where fracking will continue to take place,” Clinton claimed.

During her prior stints in public service, however, Clinton has been gentler to the industry.

State Department cables released by Wikileaks in 2010 show that Clinton was a major proponent of hydraulic fracturing while serving as the nation’s top diplomatic envoy. They revealed, according to Mother Jones, that with Clinton at the helm, the department “worked closely with energy companies to spread fracking around the globe,” including to countries with “scant environmental regulation.”

Clinton did give a nod to frackers last month, when delegates she appointed to the Democratic Party’s platform writing committee helped thwart an attempt by Sanders’ delegates to call for a ban on hydraulic fracturing. The committee instead settled on a provision calling for tighter regulations.

Food and Water Watch executive director Wenonah Hauter told DeSmogBlog that the compromise “sweeps the debate over fracking under the rug.”