The pipeline was not equipped with a system that sends an alert when there is a leak.
Check it out:

A pipeline has leaked 1 million gallons of oil drilling saltwater into the ground at a North Dakota Indian reservation, and some of the byproduct ended up in a bay that feeds the lake that provides the reservation’s drinking water, company and tribal officials said.

Cleanup at the Fort Berthold reservation site continued Thursday, two days after the leak was discovered. It was expected to last for weeks, said Miranda Jones, the vice president of environmental safety and regulatory at Houston-based Crestwood Midstream Services Inc.