The Syrup that Flooded a City Street: Boston 1919

A wave of molasses, thirty-five miles an hour, rolls through Boston's North End. January fifteenth, nineteen nineteen. The company blames anarchists. The court finds something simpler. Here is how a tank of syrup went wrong.

Start with the setting. Boston, nineteen nineteen. The North End is one of the most crowded neighbourhoods in the city, a maze of narrow streets and tall brick tenements, home to many Italian immigrants, squeezed between the old downtown and the harbour. On Commercial Street, right at the water's edge, stands a steel tank about fifty feet tall and roughly ninety feet across, as tall as a five-storey building and towering over the tenements around it. It belongs to the Purity Distilling Company, which United States Industrial Alcohol bought in nineteen seventeen. Inside, about two point three million gallons of molasses, the thick, dark syrup left over when sugar is made, shipped north from the Caribbean. That is more than three Olympic swimming pools of syrup. Why store so much? Because molasses can be turned into alcohol, for drinks, and for munitions. And America is about to ban the drink. Some writers say the company is racing to make as much as it can before Prohibition. The ban is ratified the very next day. The tank was built in nineteen fifteen, in a hurry, with the company's treasurer, Arthur Jell, in charge. He is not an engineer. By later accounts, he skips the basic test of filling the tank with water to check it for leaks. And from the start, it leaks.

The leaks are no secret. By one account, they start showing in the hot summer of nineteen eighteen. Neighbours see brown syrup seeping down the steel, and every time the tank is filled, it groans. Residents get used to the rumbles and the metallic creaks. The company's answer is not a repair. It paints the tank brown, so the leaks are harder to see. Nobody with power seems to mind. One historian argues that the neighbourhood's immigrants had little political power to push back against industry taking over their waterfront. Then, on January fifteenth, the weather turns. After a bitter cold snap, the air climbs above forty degrees Fahrenheit. A shipment of warm molasses has just been pumped in. Sources disagree on whether it was one day earlier, or two. Some experts suggest the molasses was fermenting inside, and the gas pushed outward. Historians still argue about the exact trigger. But it is lunchtime on Commercial Street, and the tank is about to let go.

At about half past twelve, witnesses hear a rumble, like an elevated train passing. Then a sound like a machine gun, as the rivets shoot out of the tank. Others remember a boom, and then a swish. The steel splits open, and a wave of molasses surges across Commercial Street. How big is it? The sources disagree. Some say about fifteen feet high, others twenty-five, and the memorial plaque says forty. How fast? Reports say thirty-five miles an hour, and a modern Harvard study found that credible. Either way, it is faster than a person can run. One researcher compares it to a tsunami of syrup. The wave tears into the steel girders of the elevated railway and tips a streetcar off its track. Steel panels from the tank itself are hurled against the structure. It slams into a firehouse. It rolls over two blocks of the neighbourhood, and then, slowly, it stops. And that is when the real trap begins.

Molasses is thick even on a warm day. It may have been slightly warmer than the air when the tank burst, so it flows at first, then slows as it cools and thickens. A Harvard team later tested the effect on a scale model, using cold corn syrup. Think of honey straight from the fridge, but a street deep. Anyone caught in it is stuck, and every struggle makes it worse. Horses are trapped too, and several die. Police and firefighters arrive within minutes, and so do more than a hundred sailors from a navy ship in the harbour, the U.S.S. Nantucket. They wade in and pull out whoever they can reach. The search goes on for four days. In the end, twenty-one people are dead, and about a hundred and fifty are injured. Crews wash the street with salt water from a fireboat, and cover it with sand to soak up the rest. For days, the neighbourhood is sticky. Molasses is tracked onto subway platforms, into streetcars and into homes. As one writer puts it, everything a Bostonian touches is sticky. The harbour stays brown until the summer, and for decades, writers say, the smell of molasses hangs over the neighbourhood. So who is to blame? The company already has an answer.

The answer is anarchists. Nineteen nineteen is a year of fear, after bombings blamed on Italian anarchist groups. United States Industrial Alcohol says someone dynamited its tank. It is a convenient story. It blames strangers, and it points at the very neighbourhood that has just been hit. The residents do not accept it. A hundred and nineteen of them bring a class action, a lawsuit for many people at once. The court appoints an auditor, Hugh Ogden, to hear the evidence. The hearings run for years, and experts are called in numbers rarely seen in a courtroom then, to explain steel, rivets and pressure. One account counts about three thousand witnesses. Ogden finds no evidence of sabotage. He finds negligence: a tank hastily built, overloaded and never properly tested. Modern engineers agree. One analysis, in twenty fourteen, found the steel was only about half as thick as it should have been, and brittle as well. Its rivets were apparently flawed, and the cracks first formed at the rivet holes. The company is held responsible, in nineteen twenty-five. It pays about six hundred and twenty-eight thousand dollars, by the most common figure; one source puts the order at a million. Relatives of the dead reportedly receive around seven thousand dollars each. Other sources give different totals.

The ruling matters more than the money. One author calls it among the first cases where expert witnesses decided the outcome. And construction laws change, with oversight by a licensed architect and a civil engineer. A small plaque on Commercial Street still remembers the day. The tank, the groans, the paint over the leaks: all of it was visible, to everyone except the people with the power to fix it. A wave of syrup, a company that blamed anarchists, and a court that checked the steel. Now, back to that wave of molasses, on January fifteenth, nineteen nineteen.