MARY LOUISE KELLY, HOST:
Now to a mystery that has been solved. For the past few years, old and strange objects have been washing up on the beaches along the Gulf of Mexico. Texas Public Radio's Dominic Anthony Walsh has the story of how the case was cracked.
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DOMINIC ANTHONY WALSH, BYLINE: At the southern tip of Texas, a few yards from the spot where the Rio Grande empties into the Gulf of Mexico, there's an unusual object.
So I'm looking at this big black kind of box-like thing. It's about as tall as a computer. It's rough, but also squishy.
The objects have been found on the opposite side of the Gulf, too, over in Florida and a bit further to the South.
CARLOS TEIXEIRA: In 2018, rubber bales starts appearing in the Brazilian coast.
WALSH: Carlos Teixeira is a researcher and lecturer at the University of Ceara in Brazil.
TEIXEIRA: At the beginning, we didn't know what kind of material was there, and a lot of people ask us about the source of the - they used to call them mysterious boxes.
WALSH: His team discovered that the objects had stamps from French Indochina. That's present-day Vietnam, Laos and Cambodia. That was an important clue.
TEIXEIRA: That's old stuff because French Indochina doesn't exist anymore.
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WALSH: The team looked back to World War II.
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UNIDENTIFIED PERSON: Brazilian fishermen find good fishing off their coast that pays better returns than the finny variety. The catch is crude rubber lost by the German war machine when the U.S. Navy sank three blockade runners.
WALSH: Three ships full of rubber bales sunk to the bottom of the Atlantic, just off the coast of Brazil.
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UNIDENTIFIED PERSON: Hitler's loss will help keep our war machines rolling.
TEIXEIRA: The question for you guys in Texas is how these rubber bales are arriving in the USA in Texas - in 2020 and 2021.
WALSH: The Brazilian research team believes the shipwrecks have begun rusting and perhaps have been disturbed by people trying to salvage cobalt. Whatever the cause, once the rubber bales floated some four miles up to the ocean surface, some of them were carried north. Chris Reddy is a senior scientist at the Woods Hole Oceanographic Institution.
CHRIS REDDY: If you're seeing out of nowhere a ship that we know has in its cargo that's been on the ocean floor for almost 80 years, and now you're starting to see them again, you start asking the question, why? And one of them, you know, would be the ship starting to fall apart.
WALSH: This is more than a quirky story about some rubber bales from a World War II shipwreck.
REDDY: This is a question about the integrity of ships that are on the bottom of the ocean floor that, for the most part, have oil. So there's a lot of ships that people are worried about.
WALSH: The rubber bales aren't great for the environment, either. Carlos Teixeira says there are concerns for shorebirds that might try to eat them as they break apart. And he says there are more rubber bales on the way.
TEIXEIRA: There is a new - OK? - a new release of rubber bales this year, actually.
WALSH: The team has computer models for how long it takes them to travel from Brazil to the U.S.
TEIXEIRA: Probably next year, you have new rubber bales arriving in the USA.
WALSH: Thousands of ships sank during the Second World War, and Teixeira says the cargo of some of them remains a mystery. The war ended 76 years ago, but the cleanup could continue well into the future. For NPR news, I'm Dominic Anthony Walsh on Boca Chica Beach, Texas.
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