The ship had 24 people aboard, including 23 crew members and a pilot from the Brunswick area. Twenty people, including the Brunswick-based pilot, have been accounted for and are safely off the vessel, said Griff Lynch, the executive director of the Georgia Ports Authority, which operates the Brunswick port.

The Brunswick port is a bustling automotive terminal for import and export vehicles. All channel traffic has been suspended, Lynch said. The cargo ship is on its side and visible from the pier on St. Simons Island.

#Update Evacuations of the Golden Ray’s crew continue. All vessel traffic in the Port of Brunswick is currently suspended unless approved by the @USCG Captain of the Port. #HappeningNow pic.twitter.com/F7JbdGCShU — USCGSoutheast (@USCGSoutheast) September 8, 2019

“The Coast Guard has closed the channel while they conduct this rescue effort,” Lynch said. “That is the most important thing the safety of life.”

The Coast Guard responded with two station boats from Brunswick, two MH-65 Dolphin helicopter crews from Savannah, the Cutter Heron and marine safety and engineering teams, the news release said.

“The Coast Guard will lead the investigation to determine what transpired,” Lynch said. “It was not an obstruction in the river or anything like that. It appears to be a vessel issue and solely a vessel issue. We are sure it didn’t hit anything.”

The vessel had approximately 4,200 vehicles on board, he said.

A @USCG Air Station Savannah helicopter crew and port partners rescued 20 people early this morning after the Golden Ray, a 656-foot vehicle carrier, was reported disabled and listing. 4 crew members are still unaccounted for. Video available here: https://t.co/WxHwVs9LPN pic.twitter.com/dD92UPuHH9 — USCGSoutheast (@USCGSoutheast) September 8, 2019

Though much is not known about the incident, Lynch said, "It seems to have to been a stability issue on the vessel.”

The Golden Ray, which is registered out of the Marshall Islands, arrived in Brunswick on Saturday evening and off-loaded “a couple hundred” vehicles and about 300 vehicles were loaded onto the ship, Lynch said.

The vessel departed Brunswick for a scheduled visit to Baltimore and from there was to travel to the Middle East, Lynch said.

The Golden Ray called on Jacksonville prior to arriving in Brunswick, according to vesselfinder.com.

In this photo provided by the U.S. Coast Guard, the M/V Golden Ray cargo ship is shown capsized near St. Simons Island, Georgia.

Georgia Ports Authority spokesman Robert Morris said an incident like this is the first of its kind for a vessel at either the Brunswick or Savannah ports.

The Coast Guard said it has established a safety perimeter around the vessel and no water craft are permitted within a half-mile.

According to vesselfinder.com, the Golden Ray was built in 2017.

The Coast Guard said it is being assisted in the rescue effort by the state Department of Natural Resources, Brunswick Bar Pilots Association, the Glynn County Fire Department, Moran Towing and SeaTow.

At a press conference Sunday afternoon about the incident and rescue effort, Capt. John Reed, commander of Coast Guard Sector Charleston, said that "flames have gone out, and the black smoke has ceased," but that officials could not confirm the fire has been extinguished until they are able to get inside the ship.

In this aerial photo provided by the U.S. Coast Guard, the M/V Golden Ray cargo ship is shown capsized near St. Simons Island, Georgia, on Sunday, September 8, 2019.

“Once salvage professionals have determined the vessel to be stable, we will identify the best option to continue our rescue efforts for the four crew remembers who remain on board,” Reed said.

It’s unclear how much fuel might be aboard the Golden Ray. The Department of Natural Resources said in a news release it has deployed an emergency spill crew and is monitoring the situation.

The DNR advised beachgoers to avoid swimming or wading in the waters at St. Simons Island and Jekyll Island until more is known about the environmental impact of the capsizing.

The Coastal Resources Division of the DNR will conduct water quality sampling to ensure the safety of shellfish harvesting beds and swimming beaches, officials said.

The Brunswick News reported Sunday that a witness said the Golden Ray passed through the channel as a second ship approached the port.

The second vessel made it to port without incident.

Cap Fendig is a local tour boat operator and distant relative of Brunswick harbor pilots. He said his boats were part of a massive multi-agency response to the incident.

The area of the channel where the Golden Ray capsized was charted by the British in the late 1700s.

“It's really not changed in width or depth in a couple hundred years,” Fendig said. “It was a port of entry declared by George Washington.”

Fendig said Sunday’s incident brought back “haunting memories” of a November 1972 incident in which a cargo vessel struck the former draw bridge in the channel that led to the deaths of 10 people. That bridge was replaced about 16 years ago by the new Sidney Lanier Bridge.

"It's an area since the 1700s all ships coming into Brunswick have turned that route and traveled that route," he said. "It's an age-old deep-water route."