Any discussions on Capitol Hill about safety improvements, however, are oddly divorced from the most pressing issues: Revitalizing an aging web of pipelines as well as understanding the liabilities associated with the growing advance of a fundamentally different form of oil in the more corrosive tar sands oil that our network is not designed to move.

Amid this void of adequate pipeline safety rules, we are marching blindly towards permitting America's longest tar sands oil pipeline - the proposed TransCanada Keystone XL pipeline.

The oil spilled into the Yellowstone River could not have come at a worse time for Montanans and the state's famed wildlife. With the river at high flood, the oil is being carried into neighboring fields and yards. It is moving fast downstream where it may affect bird habitat. It is being pushed into branch streams that likely harbor fish spawning grounds.

The proposed Keystone XL tar sands pipeline would move even dirtier, more corrosive oil that's more likely to cause leaks. Scarily enough, Keystone XL would also cross under the Yellowstone River, just like the leaky Exxon pipeline, and then continue through the Nebraska Sandhills and the Ogallala Aquifer to the refineries of the Gulf coast.

Given the images we're all seeing of the Yellowstone spill - and before it the Kalamazoo spill - it's horrifying to imagine how much more devastating a spill from the larger, higher pressure, and more toxic Keystone XL tar sands pipeline would be to this same ecosystem.

Here's the problem with our pipeline regulatory system today: Exxon was living up to federal pipeline safety standards. The Exxon pipeline's safety had already been called into question by regulators, but the Department of Transportation only took action after the spill.

This raises good questions about why our pipeline safety oversight seems to be based on reaction to oil spills rather than focused on preventing oil spills.

We do not need regulators to tell us that a pipeline gushing tens of thousands of gallons of crude into the Yellowstone River isn't operating as safely as it should be. We need our regulators to proactively evaluate the risks of spills and create standards to ensure that our wild blue rivers don't turn black in the first place.

A spill from the proposed 830,000 barrel per day Keystone XL tar sands pipeline could dwarf the current spill. A leak in Keystone XL could send nearly a million gallons of raw tar sands crude rushing into the Yellowstone River with potentially catastrophic results.

TransCanada, which is planning Keystone XL, has had an abysmal record. Its first tar sands pipeline, Keystone I, has had more than thirty leaks in the United States and Canada in less than one year of operation.

Meanwhile, the State Department is rushing forward in its evaluation of the proposed Keystone XL tar sands pipeline without a thorough study of its risks. The final environmental impact statement is expected in mid-August and a permitting decision could be made as early as the end of the year.

Ironically, Congress is considering legislation that would force an even earlier decision on the proposed Keystone XL tar sands pipeline at the same time that it is also having a series of hearings to look at pipeline safety needs in the United States.

Instead of pushing an unnecessary and risky pipeline, Congress should stay focused on pipeline safety.

Tragedies like the Yellowstone River spill can be prevented by strong safety standards, proactive action by regulators, and by saying no to dangerous pipelines - such as Keystone XL.

Susan Casey-Lefkowitz is director of the Natural Resources Defense Council’s International Program.