Law360, New York (February 25, 2015, 11:07 AM EST) -- Since the April 2010 explosion at the Deepwater Horizon rig and the ensuing 87-day oil spill from the Macondo well, oil-field developer BP American Production Company and its affiliated companies ("BP") have sought additional-insured status under $750 million of primary and excess liability policies issued to rig owner Transocean Offshore Deepwater Drilling Inc. and its affiliates ("Transocean"). Transocean and its insurers have argued that BP was only entitled to additional-insured coverage for above-surface pollution liability since the drilling contract between BP and Transocean required BP to indemnify Transocean for subsurface pollution....