When the Coast Guard saved New York from a huge blast

In the early evening of April 24, 1943, the Coast Guard braved leaping flames and saved New York City from what could have been the largest man-made explosion in history to that point, a blast that would've wiped out sections of the harbor and, potentially, large swaths of the larger city and parts of New Jersey. Instead, just one ship (SS El Estero) was lost and zero lives.

While all the other branches rib the Coast Guard for being a band of puddle pirates, it's important when really looking at its history to remember that, first, they actually have conducted a ton of deepwater missions. And, more importantly for this discussion, the shallow waters of the world are home to vital and dangerous missions that the Coast Guard does well.

The Coast Guard often takes on a large role during conflicts to help to ensure that war materiel is safely moved from industrial powerhouses in the U.S. to theaters of war overseas. During World War II, this included loading many of the Liberty Ships and other vessels that plied the Atlantic and Pacific.

But logistic expediencies created real hazards. It made sense in terms of speed and efficiency to move all the munitions, vehicles, and other vital supplies to a handful of ports and load it on ships from there. But doing so meant that strings of railroad cars and ships filled with explosive materials would be stored right next to each other.

On Saturday, April 24, Coast Guardsmen working on explosive loading details finished loading 1,365 tons of ammo onto the Panamanian freighter El Estero. But before they could even get fully aweigh, smoke started to come up out of the ship's passageways.

Investigations would later reveal that the boiler had likely been leaking fuel oil into bilge water in the compartment below it, and a boiler flashback ignited the pooled fuel and started a fire. But once the fire was going, it would be able to boil oil to give itself more fuel and heat up the ammo until it started to explode.

The engine room crew immediately started fighting the flames with handheld extinguishers, but it wasn't enough, so officers went to the Coast Guard barracks for volunteers. Could someone, anyone, please climb onto the burning ship, descend into its belly, and fight flames in the hopes of it not blowing up?

But the Coast Guardsmen knew what was at stake. The loading docks were always filled with ammo and fuel and, on April 24, there were two other nearly full ships nearby, there were railroad cars loaded with ammunition waiting to unload, and there was a fuel farm that served the departing ships. A detonation on the El Estero would likely trigger a chain reaction.

And explosions like this had happened before. Before the U.S. joined World War I, American firms sold arms to each side under equal terms, but British buyers were able to secure more credit while German ones were unlikely to even be able to get their purchases to the fighting thanks to a British blockade. So, German saboteurs blew up the shipping facilities at Black Tom Island in New Jersey, killing at least five people, destroying over million in property, and partially excavating the island.

Another World War I explosion, this one on a ship with 5,000 tons of TNT in Halifax Harbor in Canada, had killed 1,500 people leveling a large section of Halifax, Canada, in 1917. The combined loads of the El Estero and nearby ships and trains, somewhere around 5,000 total tons of explosives, dwarfed the size of the Halifax explosion. And an El Estero explosion would've been on the doorstep of New York City and could've flattened everything for five miles around.

And so 60 Coast Guardsmen, most of them in dress uniforms while awaiting their Easter Day liberty passes, rushed to the ship. New York firefighters arrived soon after with a firefighting ship, and they began passing hoses into the holds of the El Estero, but it was Coast Guardsmen who descended into the smoke and fire.

Survivors would describe a heat that overwhelmed them. The hot deck plates warmed and then burned their feet, paint peeled off the walls, and the heat continued to build. The Coast Guard officer in charge was Lt.j.g. Francis McCausland. It was his first day of work at the station.

But he was able to get tugboats to move the other ammo ships away and ordered Army soldiers to shift as many of the train cars out of range as they could move. By the time that additional fire trucks and Coast Guard fireboats arrived at 5:35, the fiercely burning El Estero was largely isolated, but still surrounded by the city, fuel stores, and warehouses of ammo.

The Coast Guard seemed to get the upper hand on the ship for a few minutes as the oily black smoke gave way to yellow and white streaks of flames, a signal that streams of water were hitting the major source of the fire. But the oily smoke returned, and the heat continued to rise.

About 40 volunteers were ordered off the ship, and a crew of 20 stayed onboard to try and keep the fire contained as long as possible while the ship was towed to a safe detonation point. Those 20 passed their personal effects to the men ordered off, some of whom wanted to stay and keep working. These included an engaged man who had to personally be ordered off the decks.

The further the ship was out of the harbor, the more lives would be saved in New York City and in the surrounding harbor from the pending explosion. Coast Guardsmen shoved anti-aircraft shells from the decks into the water and kept directing the water from the tugs onto the hot ammo as they traveled.

Miraculously, their work was enough, and the ship was towed out as the nearby cities prepared for an explosion that never came. Fuel barrels on the decks popped and boomed open, but the burnt and exhausted Coast Guardsmen onboard were eventually able to build up enough water in the ship to sink it.

(The ship was designed so that it could only be scuttled from one spot that was directly underneath the burning boilers, so the Coast Guardsmen could only sink it by flooding it.)

Once the hull of the ship was under the waves, the threat of a full ammo explosion was largely dissipated. Firefighters kept water pouring onto the still burning superstructure for hours until, finally, the threat was gone. No one had died in a crisis that was later found to have threatened as many as one million residents with death, injury, or extreme property damage.

All the Coast Guardsmen involved were given special medals for their efforts, and the U.S. government overhauled ammo-handling procedures to move dangerous operations away from population centers. This would save lives in June 1944, when an ammo ship with 4,600 tons of ammunition exploded northeast of San Francisco, killing 300 sailors on the ship and nearby, but leaving the city untouched.