If everything goes right during fracking, and the effluent that comes up the well is relieved of 100% of its gas and the resulting filth is injected in a carefully prepared well that goes deep, deep underground. The wells are to be lined and the material is to be shot far below any water, so it won't eventually seep into the water supply.
Well, it turns out it's not that easy, as the EPA announced today, no doubt on a sped-up timeline to avoid trying to put out a report under their new boss who surely wouldn't allow it.
It's actually pretty important to get this out there, since the EPA has said the opposite before. This is a bit of a win for environmentalists that has taken a lot longer than it should have to get out.