The Power of an Empty Metal Box

Season 2 • Episode 11

We’ve been shipping stuff across oceans for centuries. But until 1956, we loaded our ships in the dumbest way possible: one at a time. Longshoremen carried boxes, barrels, crates, bags, onto and off of ships one piece a time, requiring massive manpower and wasting a lot of space. 

And then Malcolm McClean came along. He envisioned lifting the big metal box part off a truck, and setting it directly down onto a ship. Every one of these boxes would be identical and interchangeable, maximizing space and minimizing waste.

What he came up with, of course, was the shipping container—an idea that was so powerful, it rejiggered the global economy, gutted cities, and turned China into the world’s manufacturer. 

Today, 95% of all goods are shipped in containers—65 million of them, carrying over $4 trillion worth every year. McLean’s vision came true—but at a tremendous cost that we’re only now beginning to confront. 

Episode transcript


Theme begins.

For 3,000 years, human beings loaded up ships in the dumbest possible way: By carrying individual boxes, barrels, bales, bundles, and bags on board, one at a time. 

But in 1956, a clever truck driver had a world-changing idea: Instead of loading and unloading individual items from his trucks, why not load and unload the entire back of the truck? 

Today, we call it the shipping container. And it changed everything: consumerism, the balance of global power, and your life.

Rooney: If you eat it, drink it, wear it, furnish your home with it, drive it—you name it, 95% of consumer goods are contained inside those containers. 

Is the history of a steel box interesting enough to fill a 40-minute podcast? You’re about to find out. I’m David Pogue, and this is “Unsung Science.”

First Ad


Season 2, Episode 11: The Global Power of an Empty Metal Box.

At, there’s a very cool tool. You can type in any phrase, and you get a graph of public interest in that term over time. When someone famous dies, you see a huge spike in people searching for that name. Same thing when a natural disaster occurs.

Well, in October 2021, searches for the words “supply chain” had a massive spike. To about three times its usual popularity. That’s because, for the first time in our lifetimes, we noticed the supply chain. We cared about it. Because…that’s when the supply chain broke. 

Rooney: So when you go back to the beginning of the pandemic in March, April 2020, manufacturing was shut down overseas, and, and then we went into lockdown. So what we saw initially was a dramatic drop off of cargo volume.  

Nobody has a better view of the global shipping supply chain than Beth Rooney. She’s the director of the Port of New York and New Jersey, the biggest seaport on the East Coast. Within one mile of the shipping docks, there’s a railroad hub, a major airport, and highways that accommodate 60,000 trucks a week.

So yeah—it’s a big port.

Pogue: And how much of that is your domain?

Rooney: It’s all of the containers that come in and out of the United States. It’s all of the automobiles.  We do most of the bulk commodities that are dry. And then we have two of the three cruise terminals. 

Pogue: Honestly, that’s so much responsibility, I don’t know how you get any sleep. 

Rooney: It’s overrated anyway. 


Anyway. When the pandemic shut down the factories in Asia, we got shortages. Car companies couldn’t get computer chips, book publishers couldn’t get paper, builders couldn’t get lumber… and everyone was hoarding toilet paper. Prices on everything skyrocketed.

But then, in late 2020, Asia’s factories reopened…and the supply chain broke in the other direction.

ROONEY: The manufacturers were working around the clock in order to catch up with everything that they hadn’t produced and hadn’t sold. 

So, you know, we have been challenged now, by the fact that there is simply more cargo that has entered into the country than consumers are purchasing. warehouses are at capacity, because there’s just more stuff than we know what to do with. 

Pogue: This whole thing, man. I mean, the last… the last couple of years has been this exercise in slow-motion over-expectation, under-expectation, reacting too late to something that’s already passed. 

Rooney: It is very reactionary. It is very reactionary. 

OK, pandemic, you’ve made your point! We get it! Every aspect of our lives relies on the supply chain. We’ve taken it for granted, it’s much more fragile than we think, blah blah blah. 

But how did we get here? 

Marc Levinson can tell us. He’s an economist, historian, and journalist, and he’s written two books about the effects of the shipping container on the world. The first one was called “The Box,” and the second, “Outside the Box.”


He says that by the early fifties, overseas shipping was excruciatingly inefficient, labor-intensive, and expensive.

LEVINSON: A typical transatlantic ship might carry 200,000 separate items of cargo. You can think of a bale of cotton. A barrel of chemicals. A wooden crate. Each individual item would be unloaded from the truck or the train, put in a warehouse alongside the dock. So each one of these 200,000 items had to be handled individually several times to get it loaded on to the ship.

And, of course, they’d have to repeat that entire process in reverse at the other end of the voyage. 

LEVINSON:  So shipping was a very, very labor-intensive business. You had tens of thousands of dock workers in places like New York and London and San Francisco. Freight transportation was very expensive. And so a lot of things just didn’t get traded. It wasn’t worth the cost of sending them. 

Now, I don’t go into these podcast interviews cold. I do my research! I do the work! Before I ever go into an interview, I watch at least one YouTube video. 

And I already knew where this story was going. I knew the legend of the shipping container. I knew the delightful story of a trucker named Malcolm McLean, M-C, L-E-A-N. 

He was born in North Carolina in 1913. When he was 21, when he was working at a gas station, he learned that the station was paying truck drivers five bucks for every load of oil they drove from the supplier 28 miles away. And bing! The McLean Trucking Company was born. It had one person on the payroll: Malcolm McLean, driving one truck.

But within a year, he had 3 trucks and hired nine drivers with trucks of their own, and they were hauling all kinds of stuff. By 1945, his company had 162 trucks, mostly hauling fabric and cigarettes. As Levinson says in his book, “He was a restless soul, competitive, calculating, always thinking about business.” 

And then came the mythical moment described in the YouTube videos. Malcolm McLean was sitting on the docks one morning, watching the longshoremen unload thousands of objects one at a time—and had a stroke of genius. There’s a better way!

I was proud to let Marc Levinson know what I already knew: 

Pogue: The inventor of the container was a guy named Malcolm McLean, like Newton’s apple hitting him on the head. 

Levinson: Uh… Malcolm McLean did not invent the container. 

Pogue: Are you correcting me, sir? 

Levinson: The concept of the shipping container had been around since the 1700s in various ways. This wasn’t new, and Malcolm McLean didn’t create it.

So wait a minute. If Malcolm McLean didn’t invent the shipping container, then why does everyone say he did? And if shipping containers had already been invented, why weren’t they a thing before he came along?

Levinson: The public really loves this idea that there is this great insight which leads to an invention. And the reality is that almost every innovation is based on previous work, previous people’s ideas, previous people’s experimentation.  

There were containers on U.S. railroads in the 1930s. There were barge companies that tried to build a business on containers in the early 1950s. But nobody found a way to make money from this. 

The problem, it seems, was that the containers were not reusable.

Levinson: What do you do if you don’t have somebody at the other end who wants to use the container? You burn it for firewood, you throw it away. So this didn’t make any financial sense. 

At least until McLean came along. His inspiration did not actually begin one morning sitting on the shipping dock. It actually begins with…hating traffic.

Levinson: Malcolm McLean was concerned because there was this big growth in auto traffic after the war. There weren’t many expressways, and all these cars were getting in the way of his trucks. And so his thought was that perhaps he could put these trucks on the ships. And so he could avoid a lot of these traffic jams. 

OK, what? The genius who revolutionized the global economy—his first brainstorm was to drive entire trucks onto the ships? 

I mean…come on. Even I could have told you that’s not gonna work. They’d be top-heavy, and they’d roll, and they’d waste so much space—no, dude.

Levinson: It became clear pretty quickly that it didn’t make sense to put a whole truck on a ship. 

This is how great breakthroughs happen: Refine, refine, refine. Try, try again. McLean modified his idea. His new concept, he called trailerships:

Levinson: So then he experimented with, “well, why not put the trailer on the ship?” And he realized that didn’t make any sense either. The trailer had a chassis with wheels. You couldn’t stack two trailers above each other. 

So idea #2 wasn’t exactly a home run, either. If you couldn’t stack these boxes, they wouldn’t save any space. 

On attempt number 3, McLean finally nailed the concept: Just put the box part of the truck onto the ship. Without the chassis, without the axles, without the wheels. That setup would cut down the space taken up by each box by a third.

Levinson: And that was the beginning of the modern container. 

McLean’s real genius was realizing that this metal box had to be part of a system. It had to be not only resuable, but hot-swappable between trucks, trains, ships, and warehouses. The same box through the whole system.

Levinson: Everybody who looked at containers previously had been trying to protect their own business. They wanted a container that was unique to them. You could use a container on one railroad, but you couldn’t transfer it to a different railroad, because it was made to fit only on a certain kind of railroad car. Malcolm McLean didn’t want any of that. He understood that for the container to actually gain traction, it had to become a standard piece of equipment that could be used widely. 

For the next three years, McLean launched into a frenzy of business shenanigans, buying, selling, and creating various corporate entities, in an attempt to work around government regulations designed to prevent a trucking company from owning ships. In the process, he actually had to sell McLean Trucking— the company he’d spent 20 years building— which at this point was one of the biggest trucking companies in the U.S.

Levinson: He placed all that money into a business that didn’t really exist yet. And that was container shipping. Malcolm McLean, in that sense, was a gamblerHe believed that you had to be fully committed to your business. 

It was a gamble. Nobody knew if the containers would survive storms at sea, how much it would cost to develop cranes or lashing systems, or if anyone would even use the new shipping service.

Levinson: He had no idea whether this business would prove viable. So he bought a ship line that had existing operating rights, and tried to run this up and down the U.S. Atlantic and Gulf coasts. He was taking a risk. 

McLean’s plan was to buy an existing shipping company called Waterman. Time was of the essence, because another company was also trying to buy Waterman. 

So on May 6, 1955, McLean and his board members met with Waterman’s board in a Mobile, Alabama conference room, trying to get the deal done. But suddenly, they realized they had a problem: Waterman’s board didn’t have a quorum! They didn’t have the required minimum number of board members present to take a vote!

So here’s the part I love. One of the lawyers runs down to the street, stops a random guy on the sidewalk, and says, “Want to make a quick 50 bucks?” They bring him upstairs, and elect him to the Waterman board on the spot. 

The deal got done.

McLean had 200 shipping containers built by a company in Spokane, Washington. To convince the government that this nutty idea was safe for both the crew and the cargo, he set up test runs, with a ship full of containers carrying cardboard boxes between Newark and Houston. Photos revealed that the boxes were safe and dry, even after sailing through storms; the government gave the green light.

Then there was the matter of designing the loading cranes, the rails that let them glide along the docks, and the spreader bar, the thing that latches onto each container from above. 

Finally, McLean was ready to take the wraps off his dream—with a maiden voyage. On April 26, 1956, a crane loaded 58 containers onto an old tanker ship called the SS Ideal-X in Newark, New Jersey. 

As she pulled out of the port of Newark, someone asked an official of the International Longshoremen’s Association what he thought of the container ship. He replied, “I’d like to sink that son of a bitch!”

But when the Ideal-X arrived in Houston, McLean and 100 dignitaries were on hand to watch it pull in. As one witness put it:

“Everybody looked at this monstrosity and they couldn’t believe their eyes. They were amazed to see a tanker with all these boxes on deck. We had seen thousands of tankers in Houston, but never one like this.” 

The cost to load that ship was about 16 cents per ton—compared with nearly six dollars a ton doing cargo the old way. The era of the shipping container had begun.

Pogue: Was there pushback, then, from these shipping lines? Who—who didn’t like the new system? 

Levinson: Many of the existing ship lines were not fans of this. They owned ships that were designed to have these tens of thousands of individual items stored in the holds. In a lot of cases, they had ships that were left over from World War II. 

So with container shipping, now, all of a sudden, they had to have a serious amount of capital to build new vessels from scratch. That drove a lot of ship lines out of the business. 

But never mind that; the economics of container shipping were too powerful to resist. By the end of the 1950s, containers were all anyone in the shipping industry could talk about. 

Unfortunately, each shipping line settled on a different-sized container! McLean’s company, eventually called Sea-Land, was using 35-foot steel containers, 8 feet tall, 8 feet wide. But the Matson line was using 24-foot boxes, and Grace Line settled on 17-footers. In Europe, they were using wooden boxes about 5 feet tall. 

So McLean had proved that containers made cargo shipping radically cheaper and more efficient. But his vision was being hobbled by the chaos of different container sizes across companies. 

Levinson: The heroes, in my view, in the story of the container’s development, were actually a bunch of engineers who spent ten years sitting with each other, trying to come up with standards for a container.  

Those engineers were assembled by the U.S. government, who told the shipping lines to get over their big bad selves and standardize the container.

Levinson: And so there was a group formed in the United States under the American Standards Association. It involved the ship lines. It involved railroads. It involved container manufacturers. It involved some interests from the trucking industry. 

They spent ten years sitting in smoke-filled rooms talking about questions like, “how thick should the end wall of a container be? Where should the internal supports in a container be? How should the doors operate on the container?”

After ten years of bickering, compromise, and voting, the industry finally hammered out the standard that we still use today: a steel box, 8 and a half feet tall, 8 feet wide, usually 20 or 40 feet long. There are variations, but those are the usual sizes. There’s a wooden floor, and doors that swing open at both ends. 

But size wasn’t the only standard.

Levinson: Very importantly, there was also a standard for what’s known as the corner fitting. Each container has, on each of its eight corners, a steel piece which has holes in it. And this is the piece that’s used by a crane to lift containers, and it’s also used to tie containers together or tie them down to the bed of a truck or, or to a train. 

Malcolm McLean contributed his patent on the corner fitting. This was hugely important, because you could put your goods into a container ship at somewhere, and at the other end of the voyage, there would be no difficulty lifting it off the ship, putting it onto a truck and getting it to its destination.

Pogue: Wow. So he, he open-sourced that? 

Levinson: He gave that patent away. He understood that this might take away a little of his business, but it could result in his company becoming much bigger, because container shipping would become a much bigger business. And that’s exactly what happened. 

And sure enough: Malcolm McLean became very, very rich.

Today, you can see these containers in photos of cargo ships, painted all different colors, towering scarily high, laid 20 across and stacked 10 high on the ship. And pro tip: There are even more containers below the decks that you don’t see. 

And once they get to land, they can go directly onto trucks and trains, although the Port Authority’s Beth Rooney says they’re not completely identical to normal truck trailers.

Rooney: The difference between an ocean container and a domestic trailer is generally the corrugation. So most ocean containers are corrugated steel, whereas domestic trailers are longer, usually 53 feet, and just flat. 

Pogue: Oh, interesting. So on a given highway, I can say to my kids, “that one came off a ship, and that one probably didn’t.” 

Rooney: I do it all the time to my daughter. 

Pogue: But is she like, ‘Okay, mom,’ at this point? 

Rooney: No, no, no, no, no, no. She’s, she’s cool. Thankfully, she’s thought I’ve been cool the whole time. I never went through the, you know, ‘don’t talk to me in public’ phase. 

Even Malcolm McLean could not have predicted the staggering immensity of the changes that this steel box would produce—in geopolitics, in consumerism, in every single human life—and in the planet itself. You’ve heard the “before” part of this story. After the ad break—the “after.”

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If you’ve followed our story this far, you now realize that Malcolm McLean may not have invented the shipping container, but his insights made it take off and change everything. The effects of that humble box—oh man, where do we begin? Or end?

Before the container, shipping accounted for about 10% of the cost of anything imported into the U.S. Today? It’s well under 1%. Shipping costs for a flat-panel TV from China are about two bucks. 

So: More goods, less expensive goods, and the freedom to manufacture them anywhere. Those were the intended consequences of Malcolm McLean’s plan. But there were a few unintended consequences, too—and we’re still coping with them today. I’m going to tell you about five of them.

First, national security. As the number of containers shipped bloomed into the millions per year, national security became a gigantic worry. We were just blithely unloading unknowable cargo from other countries, not all of whom are necessarily friendly… I mean, remember 9/11? 

Port director Beth Rooney sure does.

Rooney: I’ll be the first to tell you, on September 12th, you know, there was next to no security when it came to the maritime industry. You used to be able to drive down to a dock and sit right alongside a ship and watch the cargo, you know,  come on and off, you know, sunbathe, fish, you know.  You can’t do any of that any longer. There’s a multitude of layers of security that are in place now. 

Well, that’s impressive, considering that 9 million containers come through her port every year.

Pogue: Are they tracked? Do you know what’s in them? Do you know who’s sending them? 

Rooney:  So, yes. We know not only what’s in the container, but what’s on the ship, where’s the ship coming from, who’s on the ship.

We know this, thanks to new regulations and protocols that she helped to devise in the years after 9/11.

Rooney: So every container goes through a portal, several portals, that are scanning the container contents for any sign of radioactive material. 

Pogue: And the idea here is you don’t want nukes coming into the country? 

Rooney: Correct. 

Of course, not everything that sets off the radiation detectors is a nuclear weapon.

Rooney: There are many naturally occurring radioactive-material things that get imported into the United States. Things like kitty litter, shoe polish, ceramic tiles for your bathroom. But Customs and Border Protection knows what’s inside the box, and they know what type of signature it gives off. And they’re able to compare the two and say, “OK, this is kitty litter. It’s good to go.”

But every now and then, we’re very glad to have those radiation detectors.

Rooney: I can remember there being a shipment of catering chafing dishes that were built from material in the, like, the Chernobyl fallout area. 

Pogue: Oh, my g…. 

Rooney: So those types of things get seized, and they get destroyed, or they have to be reexported. 

Pogue: And is that the only thing that they can scan for? Is it the only— 

Rooney: No. No. They’re scanning for much more. So, for example, you say you’re importing a container of cotton balls, but the container weighs 30 tons. So those types of anomalies create a flag in their system, and then they will target those containers for a physical inspection when they get to the United States. 

There will be an X-ray or a gamma ray taken of them. They’ll see every little thing inside the container. So they’ll see if there’s, you know, false walls or false ceilings. 

They’re looking for, you know, radioactive material, you know, chem-bio material, weapons, drugs, money. They’re looking for intellectual property rights violations. 

Such as counterfeit Prada handbags or fake Rolex watches that might make their way to the streets of New York.

Rooney: They basically seize those materials if they’re, if they’re knockoffs. 

Unintended consequence number 2: containerization rearranged which cities and countries were winners, and which were losers.

Levinson: So, for example, there were hundreds of factories in Brooklyn making almost everything. One reason for that is that Brooklyn was convenient to the docks. It was easy to get your product out to a ship. 

A lot of these factories were multi-story buildings, because land in Brooklyn is limited and expensive, so you had to build upward. But once container shipping came along…

Levinson: Now you could take that factory to New Jersey or Pennsylvania or some other place, build a modern factory on a single level, and move the goods by container in a truck or a train. 

And you can find many other cities where this occurred. Boston. Baltimore. San Francisco. Industry didn’t need to be there anymore. 

Pogue: And there were probably cities that became important after the containerization, just because of where they are. 

Levinson: Sure. A great deal of manufacturing that used to be in the north relocated to the south. It’s hard to imagine that occurring without the container. But many companies found it worthwhile to move production overseas. 

Ahhh, here we go. Yeah, this is the big one. This is where we draw a direct line between Malcolm McLean…and China becoming the manufacturing center of the whole world. Unintended consequence number 3.

I’m sure you’ve heard the usual explanation for why China manufactures everything: Cheap labor, right? The can get away with paying people very little in those factories. But Marc Levinson’s got a different theory. 

LEVINSON: Well, labor costs are less than in the United States, but they’ve been less than in the United States for decades and decades, and production had never moved there. What made it sensible to move production there was that transport costs fell so much, and transport became so much more reliable. It’s not possible to imagine China being the manufacturing powerhouse that it is without the container. 

In the 1980s, the world changed again with the invention of another box: a little thing called the PC. Computers made it cheaper to communicate long distances.

LEVINSON: So now all of a sudden, a company located in one country could closely oversee what went on in another country. This made it possible for large companies to break up their production process, put each piece of it where they thought it was most efficient. You could have a factory in one country, put the goods into a container and ship them to another factory in a different country for further processing.

They might have six or seven or eight links in that chain. And so you have this extremely complex system of manufacturing goods, which is totally unlike anything the world has seen before. 

In other words, these two inventions—the container and the computer—led to the creation of…say it with me now… the Supply Chain!

And unintended consequence number 4: container imbalance. You probably know already that our supply chain is lopsided. We import a lot more stuff from Asia than we export. So I had to ask Beth Rooney… 

Pogue: So doesn’t that leave hundreds of thousands of empty containers on our shores? 

Rooney: You had to go there! So you’re right. What we have seen is an accumulation of empty containers in the Port of New York and New Jersey region. We estimate around 200,000 right now that have been accumulating because of this imbalance of trade, and then that creates a problem because it’s taking up necessary capacity. 

Pogue: What’s the solution? Does this just go on forever, piling up empty boxes? 

Rooney: No. I’ve been talking to the ocean carriers since early this year with regards to what I saw as this looming, you know, problem. I asked them all to provide us with a plan to evacuate their empty containers. And there’s lots of different ways to do that. Some are sending empty containers by rail out to the West Coast or the cargo that leaves here by rail. 

And then, of course, the other option is, is something called an empty loader or a sweeper vessel. And it would be a ship that would come in just to take out the empty containers. 

But even with all of those efforts, we’ve still got too many empties sitting here. So last summer, Beth Rooney’s department invoked…the nuclear option: Charging the shipping lines for leaving their empties on our shores.

Rooney: So the container imbalance fee would serve, we hope, as an incentive to the ocean carriers to evacuate their empties in whatever way works for them.

Finally, there’s Unintended consequence number 5—a really, really dire one. 

LEVINSON: Container ships emit a lot of greenhouse gases. They use something called bunker fuel, which is literally the bottom of the barrel. It’s really quite dirty to burn. I don’t think anybody disputes that. So there’s a lot of discussion now about how to decarbonize the transport system. Many of the container ship lines are actively involved in this. 

One idea is to slow the ships down, which burns less fuel and produces less pollution. And sure enough, container ships nowadays tend to sail at 16 or 17 knots, instead of 22 or 23 like they used to—in part because new regulations are coming into play.

Another idea is to stop using bunker fuel. 

LEVINSON: There are ideas for using ammonia as a ship fuel or hydrogen as a ship fuel or other things. But it’s pretty complicated, because if you’re a ship line, you’re operating in hundreds of ports around the world, and you have to have a supply of fuel in all of these places. So it’s not a simple transition. 

Pogue: But aren’t we farther ahead with containerization than we would have been before in terms of emissions? Because everything’s standardized, you can fit more onto one ship route. 

Levinson: But of course, that only applies if the ship is full. If you’ve got a ship that’s capable of carrying 12,000 truck-size containers and it’s half empty, you’re not doing anything good for the environment, because you’ve still got to run that engine. This was the situation in the shipping industry during the twenty-teens. Many ships were running around the world well under capacity. 

So yeah, we’re gonna have to fix the bunker-fuel problem.

And all of this came from the mighty, restless brain of Malcolm McLean. 

And whatever happened to him? Well…in 1969, he sold his company, Sea-Land, to the RJR Tobacco Company. From there, it was split apart and merged and reconstituted and bought and sold over the decades. Today, a distant descendant of McLean’s company is a division of Maersk, the second-biggest shipping line in the world.

Along the way, McLean himself became a multi-multi-millionaire. In 1982, he landed on the Forbes 400 Richest Americans list, with a net worth of $400 million. On the other hand, a couple of years later, he made a bad bet on oil prices, and wound up filing for bankruptcy, 1.3 billion dollars in debt. 

McLean died at home in New York on May 25, 2001, age 87. Heart failure. On the day of his funeral, container ships all over the world blew their whistles to honor him. Probably sounded like this.

But in a way, we’re always honoring Malcolm McLean—millions of times a year. Today, 95% of all goods are shipped in containers—65 million of them every year, carrying over $4 trillion worth of stuff. 

That steel box supercharged consumerism, made China the global center of manufacturing, and reshuffled the fortunes of cities and industries.

Levinson: The containers made the modern world economy possible. It made it possible for businesses to rethink how they produce their goods and where they located their operations. 

The container has given us immensely more choice of products at much lower prices than were imaginable before the container came along. You can go to a grocery store or a discount store today and see tens of thousands of different items for sale. The container is what gave you that choice.

Pogue: I mean, it just blows my mind. We know who Jonas Salk is, who created the polio vaccine. We know who Thomas Edison was, who helped develop the electric light bulb. No one’s ever heard of Malcolm McLean. Levinson: His contribution was figuring out a way to make this concept work. McLean had the foresight to look beyond his trucking business, and to look more broadly at the freight transportation system and to see the possibilities.