InsideClimate: Sometime before April 7, ExxonMobil will finally tell regulators and the public why its 1940s-era Pegasus oil pipeline split open in Mayflower, Ark. last March, spilling thick Canadian dilbit into a neighborhood and nearby cove. Will Exxon just send out a statement announcing its conclusions about the cause or causes of the Pegasus spill? Or will it also make public the details and supporting evidence behind its determination? If Exxon doesnt provide those details, will they be made available by...