Well, it happened.

176,000 gallons of crude leaked into a creek in North Dakota.

The leak wasn’t detected by the pipe’s owners. It was discovered by a local.

Officials aren’t sure yet what caused the leak, so let’s instead briefly talk about why pipelines fail in the first place.

Pipelines are composed of carbon steel. These pipes eventually leak because crude oil contains water and water is generally corrosive. Some oil sources, such as oil from the Tar Sands, contain more water than others.

This water sinks to the bottom of the pipe and mixes with organic materials to form a sludge. This sludge, in turn, provides nutrients for bacteria. The little critters produce sulfur as a bi-product of their metabolism and the sulfur contributes to pipe corrosion.

The first sign that something is amiss with a crude oil pipe is what’s known in the industry as a pinhole leak.

The following are resources for those of who are planning to shine light on this issue.