Emails from Hillary Clinton’s time as secretary of state show she tried to spread the practice of fracking to other countries, although now she is making campaign promises to allow communities to ban the practice.

Fracking, or hydraulic fracturing, is the process of injecting water and other chemicals into layers of shale rock to release oil and natural gas trapped within and is widely credited with sparking a boom in U.S. energy production in the last decade. Clinton was the nation’s top diplomat at the time, and emails uncovered by The Intercept show she tried to get other countries to use the same method.