Explosives will be used to remove large section of Key Bridge from Dali

Within the next week, crews plan to use precision explosive charges to remove the large section of the Francis Scott Key Bridge draped across the bow of the Dali freighter.

Charges will be placed on the truss, said Coast Guard Petty Officer Ronald Hodges of the Key Bridge Unified Command, and the crew still aboard the Dali will shelter in place on the container ship when they are detonated.

Officials at Unified Command determined the explosives would be more effective than cutting apart the piece with powerful saws —the method used so far to separate many of the bridge pieces in the Patapsco River so they can be lifted out by massive cranes.

“It’s the safest and the quickest way, rather than having a guy up there in a crane cutting a truss that’s under a bunch of weight and tension,” Hodges said. “You have these precision cutting devices that are able to serve that same function, but in an instant, rather than doing it over days and days and days, with a worker up there right next to it.”

The goal is to complete the detonations within the next week, Hodges said, but the precise timing will depend on the completion of other steps that must happen first. For instance, crews have been using cranes to relocate some of the items aboard the Dali to one side or another, so that when the large section of truss is removed, the ship will remain stable, Hodges said. Bad weather can delay those operations, he said.

“They’re still doing crane operations, so wind is a big factor that you have to take into account for when you’re operating the cranes. Lightning is the other big, huge consideration,” Hodges said. “Crews are able to work throughout the rain, in a limited capacity, but lightning and wind are a big thing that could potentially shift the date.”

It is likely that the truss sections will fall into the water once the explosives are detonated, and will be removed later by the cranes working the site, Hodges said.

Once the massive ship is freed from the wreckage, it will be refloated and removed from the site.

Last week, officials said they expected to relocate the ship by May 10 , but weather and other factors could delay that timeline. On Tuesday, the Unified Command Center announced that the body of the sixth and final construction worker killed in the collapse was recovered from the Patapsco River — more than 40 days after the bridge fell on March 26.

The Unified Command plans to send a news release with more information about the explosives 48 hours before the detonation, Hodges said.

He declined to comment further on the types of explosives that will be used, but referred to them as “precision cutting devices.”

Hodges said the contractor in charge of the project is Fort Lauderdale, Florida-based Resolve Marine, a global vessel salvage, emergency response and specialized marine services firm, but it will use Controlled Demolition Inc., a firm in Baltimore County’s Phoenix, as a subcontractor.

The local company’s president declined to comment, deferring to the Unified Command center.

Controlled Demolition was founded in the 1940s by Jack Loizeaux, who used dynamite to remove tree stumps throughout the area. It went on to become a national firm handling a variety of demolitions, including the remains of the original Sunshine Skyway Bridge over Tampa Bay in Florida; the remains of the Alfred P. Murrah Federal Building in Oklahoma City after its bombing in 1995; and the Kingdome in Seattle. It also was involved in developing the cleanup plan for the World Trade Center site in New York after 9/11.

On the Key Bridge, it’s likely crews will use devices known as “linear shaped charges,” angled pieces of metal with a small amount of explosive attached, said Nick Glumac, a professor of mechanical engineering at the University of Illinois whose research focuses on explosives.

Each explosive is likely the size of a hand grenade, and when it detonates, each piece of metal essentially becomes a knife, capable of slicing through the piece of steel to which it’s attached, Glumac said.

“It has the same effect as plunging a knife into a stick of butter to make a cut, except it’s much, much, much faster,” Glumac said.

These types of charges are part of the “standard repertoire” for marine salvage and demolition companies, Glumac said, and they’re commonly used when an area is difficult to reach or there could be a hazard to crew members if cutting is done up-close.

Duke Long, president of Wisconsin-based Interstate Sawing and Demolition, said he worked on the demolition of the Broadway Bridge in Arkansas, during which cutting explosive charges were deployed, wrapped in specially designed blankets to contain each blast.

Using localized explosives is often a safer bet than lifting a person via crane to make individual cuts one at a time, Long said.

“You’ve got a man up there in a basket, and it can kill the guy. So, that’s a very dangerous proposition,” Long said. “You put a charge on it, and everybody’s clear.”

Because the blasts are so localized, a person likely only needs to be a few hundred feet away behind a barrier when the blasts go off, Glumac said. So, it makes sense that the crew of the Dali would be able to remain on board.

Viewers watching the Key Bridge site on detonation day can expect to see small bursts of smoke where each charge detonated, and to hear a rumbling sound, Glumac said. The better show might be what happens next — when the bridge sections tumble off the bow of the ship into the Patapsco.

“Other than just smokiness around each charge, it’s not a big fireworks display,” Glumac said. “These things don’t really put on a show, in that regard.”

Maryland Gov. Wes Moore and officials with the Unified Command have been using the term “precision cutting” rather than explosion in their remarks about the operation.

Noting last week that crews had removed 182 containers from the ship, Moore said: “We can access that part of the bridge that’s directly on top of the Dali. We need to cut and clear it, and that work is remarkably complicated. We’re talking about a massive piece of steel.”

Moore likened the process to what was used to dismantle the Governor Harry W. Nice/Senator Thomas “Mac” Middleton Memorial (US–301) Bridge between Charles County and King George County, Virginia. Crews used explosives to demolish the bridge over the Potomac on March 21, 2023.

“The strategy we will use on the Key Bridge is the same one,” he said.

At an event Tuesday in Baltimore with Mayor Brandon Scott, Moore said that “as soon as that operation, that precision cutting, is done, then we also have the tools to be able to remove that steel from the water to safely refloat the Dali and to reopen up the channel.”

Scott noted that everything is being done with safety in mind: “from the folks doing the precision cutting to the folks on the Dali … The safety of all those workers is paramount.”

Baltimore Sun reporter Jean Marbella contributed to this article.