UPDATE 2-Canada-U.S. oil pipelines resume operations after activists halt flow
* Pipelines shut down for five to seven hours
* U.S. govt looks at how to boost pipeline security
* Activists face charges after tampering with lines (Updates with background on protester arrests, adds background, quotes from regulator and TransCanada executive)
By Catherine Ngai and Nia Williams
NEW YORK/CALGARY, Oct 12 (Reuters) - Five oil pipelines disrupted by environmental protesters were back up and running on Wednesday after an unprecedented act of sabotage left policy makers and energy executives from Calgary to Washington mulling how to secure key energy infrastructure.
Protesters simultaneously broke into valve stations at five different remote locations on Tuesday to stop the flow of crude through arteries that carry millions of barrels of crude from Canada to the United States every day.
Companies operating the pipelines, which pump around 15 percent of U.S. oil consumption, shut down their lines for between five and seven hours as a safety measure before the restart, according to Reuters estimates and company representatives.
The action on Tuesday underscored the vulnerability of the thousands of miles of pipeline in the United States that deliver energy to consumers.
In Washington, White House spokesman Josh Earnest said on Wednesday the departments of Homeland Security and Transportation were "trying to get to the bottom of what exactly happened and what potential steps could be taken to ensure the safety and security of our energy infrastructure." Continued...