BALTIMORE — A crane that can lift 1,000 tons, described as one of the largest on the Eastern Seaboard, appeared near the site of a collapsed highway bridge in Baltimore as crews prepared Friday to begin clearing wreckage that has stymied the search for four workers missing and presumed dead and blocked ships from entering or leaving the city’s vital port.

Maryland Gov. Wes Moore called the Francis Scott Key Bridge’s collapse following a freighter collision an “economic catastrophe” and described challenges of recovering the workers and clearing tons of debris to reopen the Port of Baltimore.

“What we’re talking about today is not just about Maryland’s economy; this is about nation’s economy,” Moore said at a news conference, the massive crane standing in the background. “The port handles more cars and more farm equipment than any other port in this country.”

Moore went to the scene Friday and said he saw shipping containers ripped apart “like paper-mache.” The broken pieces of the bridge weigh as much as 4,000 tons, Moore said, pointing out that teams will need to cut into the former span’s steel trusses to safely lift them from the Patapsco River.

Equipment on hand will include seven floating cranes, 10 tug boats, nine barges, eight salvage vessels and five Coast Guard boats, Moore said.

“To go out there and see it up close, you realize just how daunting a task this is. You realize how difficult the work is ahead of us,” Moore said. “With a salvage operation this complex — and frankly with a salvation operation this unprecedented — you need to plan for every single moment.”

Water conditions have prevented divers from entering the river, Moore said. When conditions change, they will resume efforts to recover the construction workers. The workers were repairing potholes on the bridge, which carried Interstate 695, when it fell early Tuesday.

“We have to bring a sense of closure to these families,” Moore said.

The U.S. Coast Guard is focused on removing what’s left of the bridge and the container ship that struck it in order to clear the port’s shipping lanes, Rear Adm. Shannon Gilreath said.

Teams of engineers from the U.S. Army Corps of Engineers, the Navy and the Coast Guard — along with some private-sector experts — are assessing how to “break that bridge up into the right-sized pieces that we can lift,” Gilreath said.

Maryland’s Department of Transportation is already focused on building a new bridge and is “considering innovative design, engineering and building methods so that we can quickly deliver this project,” Secretary Paul J. Wiedefeld said.

Adam Ortiz, the Environmental Protection Agency’s mid-Atlantic Regional Administrator, said there is no indication of active releases from the ship, nor of the presence in the water of materials hazardous to human health.

Col. Roland L. Butler Jr., superintendent of the Maryland State Police, said the Federal Aviation Administration has been asked to establish a tactical flight restriction area that would begin 3 nautical miles in every direction from the center span of the bridge and goes up to 1,500 feet.

Butler advised the public to stay away from the area with drones. He said law enforcement is poised to act on any violations of that airspace.