What Was the Great Molasses Flood?

Andy Josiah

The Great Molasses Flood, also known as the Boston Molasses Disaster and the Great Boston Molasses Tragedy, was a massive accident that happened in Boston, Massachusetts, in 1919, when a large molasses storage tank collapsed. Several people were killed or injured, and the damage was estimated to be in the millions by today's standards. The Great Molasses Flood signaled the beginning of an era in U.S. history when businesses would be held accountable for causing public harm as a result of their activities.

The Great Molasses Flood was an accident that happened in Boston, Massachusetts.
The Great Molasses Flood was an accident that happened in Boston, Massachusetts.

The event occurred on 15 January 1919 at the Purity Distilling Company facility located at Boston’s North End neighborhood. The chemical firm specialized in turning molasses, which was a standard sweetener at the time, into rum and ethyl alcohol using the distillation process. A five-story, 50-feet (15-centimeter) brown metal tank awaiting transfer to a nearby Purity plant burst, simulating machine-gun sounds as its rivets flew way and unleashing a wave of 2.3 million gallons (8.7 million liters) of molasses into the street. The collapse was so severe that the ground trembled. The wave traveled at 35 miles (56 kilometers) per hour, was as high as 15 feet (4.57 meters) and covered a 160-feet (48.77-meter) width.

Buildings were uprooted from their foundations and crushed by the sheer force of the molasses wave, which was recorded at 2 tons per square feet (200 kilopascals). Twenty-one people, mostly Irish and Italian laborers, were killed, crushed or drowned by the wave and rendered almost unrecognizable due to the sweetener glaze. Additionally, 150 people were injured, and several horses lost their lives.

Alcoholic distiller United States Industrial Alcohol Company (USIA), which was the tank’s owner, as well as parent corporation of the Purity Distilling Company, blamed the Great Molasses Flood on anonymous anarchists as the culprits who exploded the tank. This theory, however, was never substantiated. The families of the victims noted that the tank had been overloaded as far back as 1915, although USIA did nothing to address the problem.

The affected poor and working-class people of Boston’s North End filed a class-action suit against USIA, then one of the country’s most powerful companies, in the aftermath of the Great Molasses Flood. After five years, the Massachusetts Superior Court determined that the collapse of the tank was due to its structural deficiencies, not an act of sabotage. The USIA eventually paid $600,000 US Dollars—the equivalent of almost $7 million USD in 2011—to the victims of the Great Molasses Flood.

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Discussion Comments


@starrynight - I actually took an introduction to law class awhile back. I remember learning about this class action suit in our business law unit! It set a legal precedent to hold businesses accountable for negligent actions.

I took think that something like this would never happen today. Not only because businesses can be sued but also because manufacturing is much more regulated today than it was in 1919!


What a disaster! It's a shame that it took an incident as large as this one to make the courts start holding businesses accountable for their actions.

I feel like if an incident like this happened today it would take a lot less time for the victims and their families to get legal remedies. I'm pretty sure a business would face further legal repercussions as well if they were negligent to this degree nowadays.

I definitely don't think the Great Molasses Flood was a good thing, but at least something good did come of it.


The statistics in this article really blew my mind. This tank was huge - five stories high and 50 feet across. Then imagine the gigantic sound it must have made when it exploded.

I can't imagine the 2.3 million gallons of sweet molasses that flowed at 35 miles an hour with a wall almost three times as high as three men. It reminds me of a lava flow off a mountain and into a town.

What a frightening experience for the victims and spectators. The molasses must have been very heavy because of its density.


What a horrific and messy happening the Great Molasses Flood must have been. I guess that there was very little or no monitoring of industrial operations in regard to safety in those days.

If industrial accidents happened to people, the only way to get compensation would be to try the court system.

I'm sure after the suit against the molasses company was settled, and the victim's families were award money compensation, that pressure was put on the government to start developing safety regulations for industrial companies and a way for victims to be awarded damages.


I always think it's amazing that there was a time in history when these kinds of things happened. Of course, if it wasn't for things like the molasses spill happening, we probably wouldn't have the same type of food quality and worker safety that we have now.

Were there any specific laws or regulations that came out of this tragedy? When were OHSA or the other food quality agencies set up? At least the court system had progressed to the point where the victims' families actually received compensation after the accident.


@jcraig - The molasses was part of a global trade triangle that involved molasses, sugar, and slaves. The molasses was mostly used for rum from what I understand. I think slaves came from Africa and ended up in the Caribbean. They harvested sugar for the United States, and then the US made molasses. Not sure who the molasses went to for sure. Maybe it was England.

Woodrow Wilson would have been the president at the time I'm pretty sure. What kind of role did he have in getting new safety regulations passed regarding the situation? I'm sure things might have turned out differently if there wasn't such a progressive person in charge of the country.


@jcraig - I actually did a report on the Great Molasses Flood of 1919 when I was in high school. The real cause was that it was a hotter summer than usual which made the molasses expand in the holding tank. Like the article talks about, the tank wasn't as sound as it should have been, and it collapsed.

It took them over six months to finally clean the whole thing up. I don't remember all the details of the cleanup, but I think a lot of it involved loading it into carts and dumping it into the ocean. I'm sure the people in town were able to get plenty of free molasses out of the situation.


I can't believe I've never heard of this before. I didn't even know molasses was ever popular enough to have plants that large to start with. Was it usually just used as a sweetener and source of alcohol instead of sugar? When did sugar start to take over as the most common sweetener?

What I'm wondering, too, is how they even ended up cleaning up the molasses. Molasses is really thick, and that much would have been a huge problem. Were they able to salvage any of it?

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