Orion‘s search for a more truthful relationship between humans and the natural world occasionally calls for the expression of outrage. The more we learn about a gas-drilling practice called hydraulic fracturing—or “fracking”—the more we see it as a zenith of violence and disconnect, impulses that seem to be gathering on the horizon like thunder clouds.

Long-time friend and Orion columnist Sandra Steingraber has been particularly vocal about the dangers of fracking. Her columns in recent issues of the magazine have frequently been dedicated to the issue; and last year, after receiving a Heinz Award for her work, Steingraber donated the cash prize to the fight against fracking in her home state of New York.

In February, Time magazine broke the news that the Sierra Club, an old and respected environmental defender, had, for three years, accepted $25 million from Chesapeake Energy, one of the largest gas-drillers in the world. (In 2010, Michael Brune, the Sierra Club’s new executive director, refused further donations from the company.) The story prompted Steingraber to write an open letter to the Club, posted below. We invite you to read the letter, which testifies to the confusion, fear, and outrage that’s pouring out of communities in gasland—but which is also, importantly, a bold call to courage.