ADN and AP.  Shell Oil Co. has secured another air permit necessary to proceed with oil and gas exploration plans in the Alaska Arctic.  The U.S. Environmental Protection Agency announced Friday that it had issued an air permit for emissions from Shell's exploration activities in the Beaufort Sea. Shell plans to begin drilling in the region as early as July. The permit applies to Shell's Kulluk drill rig and support fleet.  Last month, the agency approved air permits for Shell's Discoverer drillship and related fleet, which the company plans to [...]