AILSA CHANG, HOST:
We go to a story in Baltimore, where federal investigators are trying to understand what led to the collapse of the Francis Scott Key Bridge. A massive container ship struck one of the bridge's supports early this morning, bringing the main span of the bridge crashing down into the Patapsco River. Searchers are still looking for six people who were working on the bridge when it was hit. The catastrophe raises many questions about engineering and safety and what can be done to protect other bridges. Joining us now to talk about all of this are NPR's Nell Greenfieldboyce and Joel Rose. Hey to both of you.
JOEL ROSE, BYLINE: Hey, Ailsa.
NELL GREENFIELDBOYCE, BYLINE: Hey there.
CHANG: So, Joel, I want to start with you. What are investigators saying at this point about what exactly happened?
ROSE: Not a lot, and that is typical at this point. The National Transportation Safety Board wants to gather information. They will look at a lot of things - the ship's records, safety inspections. They will try to recover the voyage data recorder from the ship, which is like the black box on an airplane. And investigators will also look at the bridge itself. Here's NTSB chair Jennifer Homendy this afternoon.
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JENNIFER HOMENDY: Part of our investigation will be, how was this bridge constructed? It will look at the structure itself. Should there be any sort of safety improvements?
ROSE: Homendy says much of this, though, will have to wait until the search and rescue phase of this is over.
CHANG: Well, about the structure, I mean, Nell, watching the video of the accident, I mean, the bridge seemed to have collapsed so quickly once the ship hit it. Can you tell us more about, like, what kind of bridge this is, why the collapse was so immediate?
GREENFIELDBOYCE: Right. So I talked to Rachel Sangree. She's a bridge engineering expert at Johns Hopkins University in Baltimore. And she told me she woke up today and saw the video, and here's how she reacted.
RACHEL SANGREE: I wasn't shocked to see the whole bridge collapse as a result of that impact.
GREENFIELDBOYCE: That's because this is a continuous truss bridge, which basically means that each section is connected together, and she told me that's why damage to a primary support can just take down the whole thing.
CHANG: Wow. Was the bridge just too old or out of date in any way?
GREENFIELDBOYCE: Well, it was built back in the 1970s, and it was built before the terrible Sunshine Skyway accident in Florida. That was in 1980, and that disaster brought a lot of attention to the need to protect bridges from ship strikes. Interestingly, though, a few months after that Florida accident, a cargo ship actually ran into the Key Bridge in Baltimore, and back then, its protective measures worked. There was this concrete structure around the bridge support that was destroyed, but the bridge itself was unharmed. And that was seen as a success story. But that was a long time ago, decades ago, and in general, cargo ships weren't nearly as big as they are today. And it seems that in this case, this huge cargo ship overwhelmed whatever protection system the Key Bridge had around its supports.
CHANG: Well, Joel, the ship - it was clearly off course. What do we know so far about how that happened?
ROSE: Yeah. This ship is called the Dali. It's a big ship - nearly a thousand feet long, can carry nearly 100,000 tons. And it appeared to suffer an electrical failure. In the video footage from the moments before the accident, you can see the lights on the ship going on and off. The Port of Singapore says the ship's management company reported that it has - it suffered a momentary loss of propulsion. And I talked to David McFarlane. He is a maritime safety expert in the U.K. McFarlane says there would be backup power systems on a ship like this, but they do not kick in instantly.
DAVID MCFARLANE: Losing propulsion can mean you lose steerage as well, and it doesn't take long to veer off course, which seems to be the case here. The ship's crew were in a dreadful predicament.
ROSE: I should caution, though, it is still very early. We're going to learn a lot more about what happened, but initially, that is where a lot of attention is focused.
CHANG: Well, Nell, what can we do to avoid catastrophic accidents at bridges like this in the future?
GREENFIELDBOYCE: Well, you know, the experts I spoke to pointed to a lot of different things - more substantial protection around the bridge supports. Of course, there's other bridge designs that are not so continuous. And, you know, it's fair to say that most likely, whatever is rebuilt there is going to look very different from the bridge that was constructed nearly 50 years ago.
CHANG: Yeah. That is NPR's Nell Greenfieldboyce and Joel Rose. Thank you so much to both of you.
ROSE: You're welcome.
GREENFIELDBOYCE: Thank you. Transcript provided by NPR, Copyright NPR.
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