InsideClimate: In the five months since ExxonMobil's Pegasus oil pipeline burst in Arkansas, two things have become clear. Flawed, 1940s-era welding techniques used when the Pegasus was built set the stage for the rupture, and an internal pipeline inspection failed to spot the problem just weeks before the spill.
The most critical question of all, however, has yet to be answered: What caused the pipe's long-dormant flawsassumed to be J-shaped 'hook cracks,' in this caseto awaken and grow undetected until catastrophe...