There seems to be a pattern here.

The city of Charleston hasn’t imposed any rules about how many and what size ships Carnival Cruise Lines can bring to the passenger terminal. City Council just knows things will never get out of hand.

And while the United Nations’ International Maritime Organization sets cruise ship standards for an array of areas, they are just guidelines. When cruise lines ignore them, there is no penalty.

Further, the U.S. Coast Guard can inspect cruise ships when they are in a U.S. port, but once they are three nautical miles from shore, the Coast Guard has no authority.

In short, the cruise industry enjoys extraordinary latitude that few industries do. Compare it, for example, to the airlines and the myriad rules and laws imposed on it.

The differences are evident in the wake of a recent fire that disabled the Carnival Triumph and caused 4,000 people to endure an extremely unpleasant — and unsanitary — five days while the ship was towed to Mobile, Ala.

Although the ship uses American ports and carries mostly American passengers, and was towed to this country, the investigation into the accident must be done by Bahamian officials because Carnival Cruise Lines is incorporated in Panama, its offices are based in Miami and its ships fly under the Bahamian flag.

Where’s the accountability?

Last year, after the Concordia, also a Carnival Cruise Lines ship, ran aground and partially sank, killing 32 people, Sen. Jay Rockefeller, D-W.Va., called for a hearing before the Commerce Committee to examine deficiencies in the cruise industry’s compliance with federal safety, security and environmental standards.

Sen. Rockefeller called the Triumph situation “just the latest example in a long string of serious and troubling incidents involving cruise ships.”

Neither the cruise ship Fantasy, which is homeported in Charleston, nor any cruise ship that calls here, is bound by city regulations.

Failing to put such regulations into place is an unnecessary risk for Charleston to take.

Carnival Cruise Lines, like the rest of the industry, might not be accustomed to binding rules and regulations, but Charleston deserves assurance that cruise ships will not erode the community’s health, culture and livability.

The unpredictability of the cruise ship industry, as evidenced by the Triumph’s sad story, should convince Charleston’s mayor and council to support reasonable cruise ship restrictions, including shoreside power and a cap on the number and size of ships that come to Charleston.