A group of senators have quietly inserted into a Coast Guard authorization bill a provision that would allow an old wooden steamboat to operate as an overnight cruise ship despite repeated official warnings that doing so would create a floating fire trap.

The Senate fell four votes short Wednesday of moving forward with the authorization measure. But the issue is not expected to die there.

The question is whether Congress will exempt the Delta Queen steamboat from a statutory and regulatory requirement that cruise ships with overnight accommodations for 50 or more passengers be made of fire-retardant materials.

The ship has taken on outsize significance on Capitol Hill because it would bring millions of tourist dollars and hundreds of jobs to voters who live along the Mississippi River.

Sen. Roy Blunt, a member of the GOP leadership team, said in a brief interview Wednesday that he and his fellow Missourian, Democratic Sen. Claire McCaskill, are the authors of the exemption provision.

“It’s my bill,” Blunt said. “They’d like to base that ship in Missouri, south of St. Louis, and we’re getting ready to do that. But they need to be able to operate the ship to do that. So the continuation of the exemption is necessary because of the way that ship was built.”

But the Department of Homeland Security, in a previously unreported letter to lawmakers last June, said the Delta Queen represents a danger that no amount of changes to the structure will avert.

“Because of the advanced age, construction, and configuration of the Steamer DELTA QUEEN, the vessel represents an unacceptable degree of fire safety risk to its passengers and crew,” Benjamin Cassidy, the DHS assistant secretary for legislative affairs, wrote in the June 28, 2017, letter to senior members of the House Transportation and Senate Commerce panels.

DHS oversees the Coast Guard in peacetime, and the Coast Guard has repeatedly opposed several earlier attempts to find a way to exempt the Delta Queen from fire rules.

‘Fire issue’

Asked about the safety issue, Blunt said: “The fire issue is always the question. [The Delta Queen] has been functioning for a long time. …President Carter took a vacation on this boat.”

Jimmy Carter did take a voyage on the ship during his presidency, as the Delta Queen has received several exemptions from the requirement for fire-retardant materials in the past half-century, the only such ship to get special treatment.

However, the most recent of these exemptions lapsed in 2008, and it has yet to be renewed amid the safety worries.

Last April, the Senate passed a bill that is nearly identical to the one now being debated. But the measure went nowhere in the House before the end of the 2017 session.

Until Wednesday, proponents of the exemption had not been heard from this year. And they did not appear to seek attention this time, inserting the provision in the massive Coast Guard bill without any apparent public comments.

Proponents said the exemption measure would improve the boat’s safety. It would require unspecified structural alterations to 10 percent of the boat per year, focusing on combustible areas. The bill would mandate that the boiler and other key sections must have noncombustible enclosures. And there must be more than one way off the boat.

But DHS’s Cassidy wrote last year that the department “is not persuaded that allowing incremental alterations of some percentage of the vessel represents a viable solution.”

At press time, the Coast Guard had not replied to a query about the issue.

Watch: What’s the Nuclear Option? Dismantling This Senate Jargon