Federal regulators still don't have enough detail on Shell Oil's latest Arctic drilling plans to judge whether the company is ready to proceed this summer.

The Bureau of Ocean Energy Management went to Shell on Tuesday seeking more information about the company's operating and exploration plans for the Chukchi Sea. This is the second time that BOEM has come back with questions since Shell's initial filing in November.

A lot of BOEM's requests have to do with air emissions data for Shell's fleet. BOEM is taking over responsibility for writing Arctic air emissions permits from the Environmental Protection Agency starting now.

BOEM also wants to know what Shell has done to tighten up its management structure since their troubled 2012 expedition. They're looking for proof that "oversight deficiencies that allowed the physical deficiencies to remain undedicated or unresolved during the course of operations have been fixed."

To that end, BOEM is asking to see the results of an external audit of Shell's management structure. The Department of the Interior ordered the audit last year, and they won't allow Shell to go back to the Arctic until it's done.