Carnival (CCL -1.09%) will pay the Treasury Department for the government's assistance in bringing back a pair of stranded ships operated by the company. Carnival stressed that it is doing so voluntarily and that no arm of the government requested such reimbursement.

The company pointed out that "at no point has Carnival stated it would refuse to reimburse federal agencies if they sought remuneration." 

The move follows an inquiry by Senator Jay Rockefeller (D-WV) into the Triumph incident and the company's general safety record. Among other questions, Rockefeller inquired whether the cruise ship operator would foot the roughly $780,000 bill for the Coast Guard's Triumph rescue and $3.4 million for that organization and the Navy's assistance with another ship, the Splendor, which was stranded in 2010.

In the press release announcing its move, Carnival did not specify the exact dollar amount it would pay the government.