Secretary of State Hillary Rodham Clinton:

I urge you to conduct a rigorous, transparent, and thorough environmental review of the Keystone XL pipeline's northern segment, which will deliver tar sands oil from Alberta, Canada to Steele City, Nebraska.

Transporting this dirty fuel to U.S. markets has proven to be extremely dangerous, unpredictable and uncontrollable, as evidenced by the massive spill two years ago that dumped one million gallons of tar sands oil into Michigan's Kalamazoo River. The Keystone XL pipeline's route would put crucial habitat, communities, and vital water supplies — including the Ogallala aquifer, which provides drinking water for millions of Americans — at risk for a similar catastrophe.

In addition, Keystone XL would expand destructive tar sands extraction in Canada and increase global warming pollution, and this review should include a thorough evaluation of these risks. Clean energy that benefits people and wildlife is the path forward for economic and energy security in America — not another tar sands pipeline.