Four people were injured Friday morning when a Boston-bound MBTA ferry ran aground in heavy fog near Long Island in Boston Harbor, the Coast Guard and the transit authority said.
The injured were brought into the Black Falcon Pier in South Boston for transport to Boston hospitals for treatment, officials said. The extent of the injuries was not immediately known.
The ferry that ran aground, the MV Lightning, had a crew of three and 81 passengers as its crew maneuvered in the fog to avoid a sports fishing vessel that suddenly cut in front of it, MBTA spokesman Joseph Pesaturo said.
The vessel landed on rocks, and the hull above the water line was breached, officials said.
“The safety of our customers, our employees, and our vendors is our highest priority,” said MBTA General Manager Steve Poftak in a statement. “We are offering our full support and cooperation to the United States Coast Guard, which is leading the investigation into the incident. We are also conducting an independent assessment of the damage to the vessel.”
Sheila Green, a spokeswoman for Boston Harbor Cruises, which operates the ferry, said in a phone interview that workers have to check the hull of the MV Lightning for any damage before it can go back into service.
In the meantime, Green said, Boston Harbor Cruises has a large fleet of vessels and “commuter ferry service should not be impacted at all.” MBTA officials released a statement also saying service on that route would not be affected.
She said the Lightning captain wasn’t available for an interview because the investigation remains active.
Following the incident, the Coast Guard said in a statement, the ferry “got underway under its own power to dock in Charlestown. The cause of the incident is under investigation.”
A subsequent damage assessment affirmed that no ocean water ever entered the vessel, the MBTA said.
The vessel is scheduled to depart for Gloucester for repairs on Saturday, officials said.
Dieckmann Cogill, a Dedham resident who lives in Hull in the summer, was one of the 81 passengers. As usual, she was on the top deck sipping her morning coffee when the ship’s captain started blowing the horn repeatedly in heavy fog.
“It was super foggy, zero visibility,’’ she said after safely returning to land at Boston’s Long Wharf. “We turned and saw Long Island. We saw that we were too close . . . We knew we were going to run aground, but there was nothing we could do.”
When the vessel hit the rocky shore of Long Island, the boat shuddered, and Cogill said she fell forward. “My friend Kiley caught me like a football,’’ she said.
Bruce McWhorter said the ferry ran aground about 10 to 15 minutes into the trip.
“It was very foggy,” he said.
Suddenly “we heard this crash,” and people were jostled, he said.
“People just kind of lurched forward, a couple people fell down, but nobody was seriously hurt,” McWhorter said.
Pesaturo said the incident was caused by the sports fishing boat that veered in front of the ferry, which departed from Hull. The ferry was forced to take evasive action, officials said.
All of the passengers were off the Lightning by 10:10 a.m., the Coast Guard said.
The grounding triggered responses by marine units from Boston fire and police, State Police, Massport, the Coast Guard, and Boston Harbor Cruises.
Boston Fire Commissioner Joseph Finn said the Fire Department helped to offload passengers from the damaged boat with assistance from Massport, the State Police, and the Coast Guard.
The commissioner said the Fire Department hazmat team was on the way to the scene to assist, but there did not appear to be any leak from the vessel.
State Police also responded to the grounding.
“At the time of the incident, conditions included heavy fog and low tide,” agency spokesman David Procopio said in a statement. He said the ferry “ran [aground] in approximately five feet of water while inbound to Boston. State Police Marine 44, along with vessels from the other agencies, evacuated the 84 passengers and brought them to Black Falcon Terminal. Four passengers suffered injuries and have been transported to area hospitals. At least one injury is potentially serious.”
The Coast Guard is now investigating the grounding.
The ferry was making the 7:30 a.m. trip out of Hull when it ran aground, officials said. The trip is scheduled to take about 23 minutes, but for passengers on the Lightning on Friday, the trip took some three hours.
Photos posted on social media by passengers showed the left side of the vessel fully out of the water and resting on a rock.
The National Weather Service said visibility in the harbor was low because of the heavy fog.
“We had a dense fog advisory out,” said Bryce Williams, a meteorologist at the weather service office in Norton. “Quite a bit of dense fog out in Boston Harbor.”
John R. Ellement can be reached at email@example.com. Follow him on Twitter @JREbosglobe. Emily Sweeney can be reached at firstname.lastname@example.org. Follow her on Twitter @emilysweeney. Sarah Wu can be reached at email@example.com. Follow her on Twitter at @sarah_wu_. Mike Bello and Alyssa Lukpat contributed to this report.