Hillary Clinton continues to fundraise with fracking investors, despite her assertion Sunday that she would largely curtail fracking inside the U.S.

Fracking is a controversial mining technique used to extract natural gas from shale rock. It releases vast quantities of methane into the atmosphere and groundwater, frequently poisoning the water supply of nearby communities.

On Wednesday, the Clinton campaign was to hold a $575-a-head fundraising lunch at a Ritz-Carlton Hotel on the Northern California coast hosted by Alisa Wood, a partner at the international private equity firm Kohlberg Kravis Roberts & Co. (KKR).

In 2009, KKR began heavily investing in fracking, purchasing large shares of three North American oil and gas companies, and selling two of them for billions in profits. The third was hit hard by plummeting gas prices, and declared bankruptcy last year. But KKR was not deterred, and still owns a large portfolio of small fossil fuel companies, at least two of which — Cinco Industries and Comstock Resources — use fracking.

During the Democratic debate Sunday night, a student at the University of Michigan asked both candidates whether they supported fracking.

Clinton said she did, but with three big caveats:

“You know, I don’t support it when any locality or any state is against it, number one. I don’t support it when the release of methane or contamination of water is present. I don’t support it — number three — unless we can require that anybody who fracks has to tell us exactly what chemicals they are using. So 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.”

When asked the same question, Sanders said, “My answer — my answer is a lot shorter. No, I do not support fracking.”

In July, Bernie Sanders and former presidential candidate Martin O’Malley pledged not to accept donations from fossil fuel companies. Clinton did not sign the pledge.

Many of Clinton’s largest fundraisers are lobbyists for oil and gas corporations. Some of her largest contribution bundlers are lobbyists representing Chevron, Cheniere Energy, and TransCanada — all companies that use fracking.

Prior to announcing her candidacy, Clinton also received $990,000 for speeches she made to the Canadian Imperial Bank of Commerce — a heavy investor in TransCanada and the Keystone XL pipeline.

After a rally in Iowa last December, Clinton claimed to be unaware she ever received donations from fossil fuel companies. “Well, I don’t know that I ever have. I’m not exactly one of their favorites,” she said. “Have I? OK, well, I’ll check on that. They certainly haven’t made that much of an impression on me if I don’t even know it.”

An investigation by Mother Jones found that Hillary Clinton personally lobbied for U.S. fracking rights overseas as secretary of state. Speaking at a 2010 conference of foreign ministers, Clinton said, “I know that in some places [it] is controversial, but [shale] gas is the cleanest fossil fuel available for power today.”

Correction: March 10, 2016

An earlier version of this story reported that Clinton herself would attend the fundraising lunch; in fact, the guest of honor was Ruth Porat, the CFO of Alphabet.