Drill rig and well pads near confluence of Missouri and Yellowstone Rivers,

near the North Dakota/Montana border.

Drill rig and well pads near confluence of Missouri and Yellowstone Rivers,

near the North Dakota/Montana border.

Sixteen days ago, Operator Summit Midstream Partners found a toxic leak of salty drilling waste from a pipeline in western North Dakota, the heart of the Bakken oil boom. Although it reported the leak to the state's department of health immediately, it wasn't until Tuesday when officials learned that nearly three million gallons of the stuff had leaked into two creeks. This makes it the largest spill of its type since the North Dakota oil boom began about a decade ago.

A clean-up is underway, but the full extent of the environmental damage is not yet known and may not be for a long time. That, in part, is because they don't know what caused the leak nor how long it allowed toxins to spill into the creeks. Effects from such spills can last for decades. Authorities say there is no danger to drinking water supplies. Katie Valentine reports:



North Dakota Department of Health Environmental Health Section Chief Dave Glatt said he hasn’t seen any impacts to wildlife yet, but officials won’t likely know the full impact until all the ice melts. Officials have discovered chloride concentrations in Blacktail Creek as high as 92,000 milligrams per liter—far higher than normal concentrations of about 10 to 20 milligrams per liter. “That has the ability to kill aquatic life and so we’ll want to see if the aquatic life was able to get out of the way, and if they weren’t, how badly they were impacted,” Glatt said.

While this is the largest such spill, it's far from the only one. Two-and-a-half years ago, the investigative website ProPublica reported that oil companies had revealed more than 1,000 reported spills in 2011. Most of these were said to be small, but the investigation found that in several cases they were much larger than first claimed. In addition, there is considerable illicit dumping.

More on this below the fold.