One person was killed and more than a dozen had to be rescued after a tour boat capsized Monday morning while carrying passengers through a narrow underground cavern in western New York, prompting an all-out rescue effort, officials said.

Twenty-eight people were on board when the boat tipped over at the Lockport Cave in Lockport, N.Y., about 20 miles east of Niagara Falls, Luca Quagliano, the city’s fire chief, said at a news conference. Emergency workers rescued 16 people from the water, the chief said; the rest were able to get to safety on their own.

“The boat did a 180-degree turn, so the bottom of the boat was upright in the water,” Chief Quagliano said at the news conference. “A number of victims were on top of that boat initially when rescuers got to them.”

The authorities identified the person who died as a 60-year-old man who became trapped beneath the boat when it capsized. The man’s wife was also on the boat and was injured, Chief Quagliano said. He did not provide other details about the victim.

None of the passengers were wearing life jackets, the chief said, adding that because the cave attraction was privately owned, he and other officials were still trying to determine whether the cave was required to provide them.

Another line of inquiry involved inspection requirements for the flat-bottomed boat. It was not immediately clear which state agency, if any, had regulatory oversight of the attraction.

Steven Abbott, Lockport’s police chief, said the cave was being treated as a crime scene. An inspector from the federal Occupational Safety and Health Administration was among those involved in the investigation, a spokesman for the agency said.

“We have one individual who has passed, we have a lot of questions that need to be answered,” Chief Abbott said. “Whether or not that leads to charges in the future, I do not know, but as of right now we’re treating it as a crime scene.”

Eleven people were taken to hospitals with minor injuries, the worst appearing to be a broken arm, Chief Quagliano said. Of seven who were treated at Eastern Niagara Hospital in Lockport, six were released by 4:30 p.m. and the seventh was expected to be released Monday evening, a spokeswoman said.

The passengers were local residents on an outing sponsored by Destination Niagara USA, a regional tourism group that organizes such events for hospitality industry employees in Niagara County’s towns and cities, officials said. Monday was “Lockport Day.”

Andrea Czopp of Destination Niagara USA, who appeared at the news conference, said she had visited the cave “many times” and had never worn a life jacket.

The police in Lockport said a call about the boat capsizing had come in at about 11:30 a.m. The police and fire departments and other public safety agencies immediately began rescue efforts, officials said.

The boat, which can safely accommodate up to 40 people and has only about two to three feet of clearance on either side as it traverses the tunnel, became unbalanced at the end of its 300-foot route for reasons that were not yet clear, Chief Quagliano said.

Everyone aboard — 27 passengers and one employee — was thrown into the water, which was about 60 degrees and exceeded six feet in depth in places, he said.

A remnant of western New York’s industrial pasts, the tunnellike cave is adjacent to the Erie Canal and was created in the 19th century as a spillway for the canal. It opened as a tourist attraction in the 1970s. Lockport’s mayor, Michelle Roman, said the death was the first at the attraction that anyone could remember.

The cave was designed by Birdsill Holly, a businessman and inventor, to harness the canal’s downhill water flow to power equipment at his Holly Manufacturing Company, according to newyorkupstate.com. Miners blasted through limestone for eight years to complete it.

As described by tour guides, the cave’s creation relied in part on the labor of orphaned children called powder monkeys who were sent underground to tamp gunpowder into small holes, light it and then run for their lives.

Near the cave on Monday afternoon, firefighters, police officers and New York State troopers formed a human wall around people who appeared to have been rescued from the boat, many wrapped in white towels.

Ashley Kandel of Victor, N.Y., was among those looking on. She and her husband, Tarek, had been scheduled to take the cave tour at 2 p.m. She said she had sensed something might be wrong when they were on their way to the cave in the late morning.

The couple encountered a large number of fire trucks and noticed that streets in the area were blocked off, Ms. Kandel said. She called Lockport Cave to ask about the unusual traffic, but no one answered, she said.

“We were going to face our fear of being underground,” Ms. Kandel said, describing part of the couple’s motivation for taking the tour.