Revelations that preventable safety lapses were behind Enbridge's disastrous oil spill in Michigan thrust the issue of pipeline safety into the mainstream this year.

A two-year investigation by the National Transportation Safety Board in July found that a "complete breakdown of safety" at Enbridge led to the 2010 oil spill in Michigan's Kalamazoo River. The spill originated from a ruptured pipeline that spewed more than 1 million gallons of diluted bitumen (oil from Canada's tar sands) into the water. It was one of the largest inland oil spills in U.S. history and forced residents to relocate, caused health problems and left a mess that's still being cleaned up today.

The NTSB report criticized the Canadian pipeline giant for inadequate safety inspections and other human errors that resulted in Enbridge ignoring the spill for 17 hours.

An agency official compared Enbridge employees to the "Keystone Kops"—a phrase that drew immediate comparisons to a separate Keystone, the Keystone XL pipeline that's being proposed to cross the Ogallala aquifer, the nation's most important source of irrigation and drinking water.

TransCanada, the company behind Keystone and one of Enbridge's rivals, spent much of the year trying to reassure the American public that its pipeline would be the safest one ever built in North America.

But the outreach did little to soothe fears of landowners living along the route, who worry about the effects of a pipeline spill on their lands, livelihoods and water supplies—and the operator's ability to prevent and detect those leaks.

Federal records show that remote sensing systems—a major component of pipeline leak detection— detected just 5 percent of all oil pipeline spills between 2002 and July 2012, according to an exclusive InsideClimate News analysis. The public detected spills at four times that rate. (A forthcoming study by the Pipeline and Hazardous Materials Safety Administration found the same trend with all oil, gas and other hazardous liquid pipeline accidents in the past two years, The New York Times reported last week.)

InsideClimate News also learned that TransCanada has chosen not to add certain safeguards that go beyond federal standards, including advanced leak protection technology that can detect tiny spills. Those features are installed on the Longhorn pipeline, which carries gasoline across a Texas aquifer.

TransCanada has rerouted its pipeline around the sensitive Nebraska Sandhills, but it still crosses a vulnerable region of the Ogallala aquifer, through parts of Nebraska with a high water table and permeable soils. Nebraskans have spent years trying to move or stop the project.

The northern leg of the pipeline through Nebraska still needs approval from the U.S. State Department because it crosses an international border. The project's southern leg, through Oklahoma and Texas and to the Gulf Coast, is already 25 percent complete, according to TransCanada, but construction has been disrupted by activists who are trying to stop the project through civil disobedience.

In Michigan and Indiana, where Enbridge is replacing its ruptured pipeline with a larger capacity line, residents are demanding a greater role in the pipeline approval process. They want the company to take extra measures to protect rivers and wetlands. Frustrated Michigan residents filed lawsuits to force Enbridge to follow local construction ordinances.

The Enbridge and TransCanada pipelines are just two of the many projects being proposed to export heavy Canadian crude to global markets. Canada's booming oil sands industry relies on pipelines to move its product from landlocked Alberta to coastal exports ports. The industry plans to build at least 10,000 miles of pipelines over the next five years, much of it across the United States.

The pipeline boom would further tax the overburdened Pipeline and Hazardous Materials Safety Administration (PHMSA), a small, underfunded agency tasked with monitoring 2.5 million miles of pipelines.

PHMSA was forced to strengthen some of its regulations after a new pipeline safety bill became law in January. Advocates say it does little to address the problems that contributed to the Enbridge spill. And any changes to existing rules are unlikely to be in place before the Obama administration decides whether to approve the Keystone XL in 2013.