A decade into North Dakota’s shale fracking boom, the state consistently produces one million barrels of oil per day. Now, officials here look to double production.

Is having oil and gas development nearby bad for your health? In this story, we’re going to dig into what is known and what is unknown about these dangers and why those unknowns still exist, as more and more wells are drilled. We’re going to meet different people with different perspectives, who are all gathering data or studying it. They’re looking for answers and living with unknowns.