Guardian: In the months before BP’s Deepwater Horizon rig sank in a ball of fire in the Gulf of Mexico, the company had four close calls on pipelines and facilities it operates in Alaska, according to a letter from two congressmen obtained by ProPublica. In that letter, dated Jan. 14, 2010, Reps. Henry Waxman, D-Calif., and Bart Stupak, D-Mich., noted that the company’s efforts to cut costs could imperil safety at BP facilities. Between September 2008 and November 2009, three BP gas and …