Alberta's Energy Resource Conservation Board is issuing a high-risk enforcement action against Calgary-based Plains Midstream over a 2011 pipeline leak northeast of Peace River, Alta.

The 28,000 barrel spill — which leaked from the Rainbow pipeline in northern Sunrise County — was the largest in Alberta in more than three decades.

The ERCB says the company had inadequate leak detection and failed to test its emergency response plan.

While there is no fine associated with the action, Plains Midstream has been told to hire a third party to audit its ability to manage communications during a crisis.

The company also made headlines in 2012 for an oil spill near Sundre, Alta.

About half a million litres of light sour crude spilled into the Red Deer River with some of it washing into the Gleniffer reservoir, which provides thousands of Albertans with drinking water.