Last month, an engine room fire left the Carnival Triumph crippled and adrift in the Gulf of Mexico with more than 4,200 people aboard.

That scheduled four-day cruise stretched into eight days as tugs pulled the vessel into port in Alabama. Food was scarce, and passengers sweltered in the heat with no air conditioning. People aboard also reported overflowing toilets and human waste running down the walls in some parts of the ship.

A class action lawsuit was filed against Carnival Corporation in the aftermath.

The Triumph is still undergoing repair at a shipyard in Mobile, Alabama, Carnival spokeswoman Joyce Oliva told CNN Thursday.

"We are now focused on the lessons we can learn from the incident and also what additional operational redundancies might be available," Cahill said at the cruise industry conference this week.

Another ship, the Carnival Splendor, had a fire in 2010 due to "a catastrophic failure of a diesel generator," Cahill noted.

Sen. Jay Rockefeller, the chairman of the Commerce, Science and Transportation Committee, sent a letter Wednesday to Micky Arison, the chief executive officer of Carnival Corporation.

"The Coast Guard has responded to a string of 90 marine casualty incidents with passengers onboard Carnival ships in the last five years," the West Virginia Democrat wrote. "It seems that Carnival has failed to take any meaningful course of corrective action after these continual incidents. This needs to change."

Rockefeller said the cost to the taxpayers for the Carnival Triumph incident was almost $780,000.

Cahill said last week that the comprehensive review of the fleet "is our highest priority."

He also emphasized that the vast majority of the time, cruises experience no such problems.

Anderson said when he booked the cruise tickets for his family, some friends ribbed him about choosing Carnival, given what had happened with the Triumph. "I said, 'What are the odds of it happening to two ships in such a short period of time?'" he told CNN Thursday. "Look what happened now."