What Was the Great Molasses Flood?

You might be familiar with the Boston Tea Party, but for many Bostonians, there’s another food-centric event that comes to mind as they reflect on local history: the Great Molasses Flood. 

When a surge of sticky dark brown syrup washed over Boston’s North End on January 15th, 1919, it wreaked havoc on the neighborhood, killing 21 people, injuring 150, and destroying businesses and homes. The tragedy’s name might spark laughter from anyone who hasn’t heard of it — as Ayo Edebiri pointed out on Late Night With Seth Meyers, people inevitably wonder how such a notoriously slow ingredient could bring about so much harm.

But Edebiri also emphasizes that the flood is something Bostonians still care deeply about; and justifiably so, considering the gravity of what occurred. While it’s unlikely that an identically unusual and sugary tragedy could happen again, the 106th anniversary of the Great Molasses Flood presents an opportunity to reflect on the negligent circumstances that resulted in a torrent of syrup crashing through Boston, and how molasses could cause enough damage to leave a permanent mark on local minds and history.

To start understanding the Great Molasses Flood, you need to first grasp exactly how much molasses was involved. A 50-foot-tall tank, 19 feet in diameter, full of 2.3 million gallons of molasses broke open on January 15th. The wave of viscous liquid that was released reached up to 40 feet at its highest points, and traveled through the streets at 35 miles per hour. A wave of water at these heights and speeds would undoubtedly be dangerous, but molasses is denser — and consequently heavier — than water, making it even more difficult to move through.

To visualize how impactful this was, Stephen Puleo, historian and author of Dark Tide: The Great Boston Molasses Flood of 1919, says to “think of the wave as a small tidal wave that disgorged from the tank when it disintegrated, recoiled off of the back side of Copp’s Hill, and then traveled southward along Commercial Street, scouring everything in its path: people, horses, houses, carts, produce and supplies that [people delivered] to the waterfront… and debris of all sorts. It’s this debris like wood, bricks, stone, etc. that caused many of the serious injuries.”

The molasses was so strong that, according to Puleo, “The overhead train trestle for the Boston Elevated Railway that connected the north station with the south station was severed and damaged by the molasses wave and pieces of the tank. A train traveling overhead barely missed plunging to the street below.”

Firefighters, police, and sailors were quickly on the scene to help rescue those trapped by molasses, collapsed buildings, and other debris. Because the flood occurred in January, the molasses became thicker as the day grew later, and the syrup gradually chilled, making it more difficult to free anyone stuck in the liquid. Puleo notes that the liquid was thick enough that “Firefighters laid ladders horizontally across the molasses and crawled on them to pull victims out.” Some descriptions of rescue efforts detail how people were dug out of the molasses, emphasizing its tackiness.

The Great Molasses Flood was, unfortunately, a very preventable disaster. The tank holding the syrup — which was owned by the United States Industrial Alcohol Company (USIA), with the intention of fermenting the molasses into industrial alcohol for the production of munitions — was shoddily constructed from the beginning. Its walls were too thin to reliably hold the weight of all the molasses, and observers nearby could reportedly hear groaning sounds each time it was filled.

The USIA also failed to test the tank by filling it with water before putting the vessel into commercial use, which would have allowed the company to detect any possible cracks. Even before the vat burst on January 15th, local children would sometimes fill pails with molasses that had leaked from the tank — an early warning sign of the structure’s faulty nature.

As a result of the gross oversight that caused the flood, 119 plaintiffs filed a class action lawsuit against the USIA — one of the first in Massachusetts history, Dorr v. United States Industrial Alcohol Company — which would ultimately influence safety and construction standards throughout the country. The case ended in 1925, with $628,000 awarded in damages, the equivalent of more than $11 million today.

Puleo explains that after Dorr v. USIA, “the entire relationship between government and big business changed. The most visible manifestation of that today is that everything we take for granted when it comes to building construction standards — that architects need to show their work, that engineers need to sign and seal their plans, that building inspectors need to come out and inspect and approve projects — is a direct result of the Great Boston Molasses Flood of 1919.”

Even after any rescue efforts had been exhausted, cleaning up millions of gallons of molasses was a monumental task, and Bostonians said for decades following the flood that they could smell the aroma of molasses during the hot summer months. That lingering scent mimics the way the events of January 15, 1919 have stayed on local’s minds.

The flood is the perfect storm of peculiar (it was a wave of molasses after all), and also tragic. Together those two factors inevitably spark intrigue, and ensure that the events from 106 years ago today won’t be forgotten. Students at Harvard have studied the physics of the flood, and why the tank burst. There’s a children’s book that many locals may recall reading while growing up. If you’re visiting Boston, you can even take a tour to learn more about the historic tragedy. And of course, Ayo Edebiri is doing her part to ensure that no one will forget about the Great Molasses Flood.