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What Happened When A Great Wave Of Molasses Flooded The Streets And Claimed Countless Lives

Even though it happened over 100 years ago, the Great Molasses Flood made its mark as one of the most bizarre and tragic stories in food history. On a cold winter day in Boston, MA, just around lunchtime, a tank of molasses exploded in the city’s North End. Over two million gallons of the sugary and thick liquid began to flood the streets. While it may seem like the syrup would move slowly and be easy to avoid, that was not the case. The molasses spread quickly and viciously, like a tsunami wave. At its most dangerous, the syrup reached speeds of 35 miles per hour.

The visual might seem fantastical. But the accident that took place on January 15, 1919, was much more than a simple food spill. The thick liquid completely flooded the town.

Lives were lost; buildings were destroyed. Unfortunate residents of the Boston, MA, locale got trapped as did animals of all sizes. The havoc took months to clean up. And the smell of molasses allegedly lingered in the Massachusetts streets for decades.

But how did a disaster like this even occur?

Over a century later, studies are still revealing new information about what caused the tragic events that took place on that cold winter day. Some might even mistakenly assume the situation is farcical. But Mark Rossow – a civil engineer who studied the accident – said, “First you kind of laugh at it, then you read about it.” That’s when the terror truly sinks in.

Here’s everything that happened on the fateful day of the Great Molasses Flood.

Boston, MA, Was In A Weird Transitional Period At The Time.

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Just two months before the accident took place, World War I ended. And it was referred to as the “War to end all wars.” Many soldiers were making their way back to Boston and starting to transition back to normal life.

The transitional period affected everyone.

According to reports, the city was moving in an unnatural rhythm to begin with. Consequently, many people were in the wrong place at the wrong time when the flood started.

It was a turbulent time for the government as well.

Along with the conclusion of the war efforts, Prohibition was gaining momentum across the country. And alcoholic beverages were frowned upon in many public spaces.

Eventually, Prohibition was repealed.

But at the time of the flood, only one more state needed to ratify the 18th amendment and thereby make the sale and consumption of adult drinks illegal.

The owners of the molasses tank that caused the flood was a subsidiary of the United States Industrial Alcohol (USIA).

Purity Distilling Company owned the molasses tank and built it in 1915. And their million-pound vessel was wholly responsible for the catastrophic event. In fact, their parent company, the USIA, made a huge profit during the war by using the molasses to process and distill alcohol.

The tank was highly explosive to begin with.

The molasses that was stored in the tank was used along with highly flammable substances like TNT and nitroglycerin throughout the war. Overall, the vessel was like a ticking time bomb.

A Terrifying Play-By-Play

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Yes, it’s sweet. But molasses syrup is sticky and annoying enough when it spills onto a table or countertop. When the spill is of a greater magnitude, though, things get more than messy.

Understandably so.

And things move incredibly quickly. Over two million gallons of the thick liquid exploded into the streets in January of 1919.

The initial rush was impossible to stop.

Traveling at a speed of 35 miles an hour, the molasses flood moved as quickly as some vehicles. People were not able to outrun the danger for long periods of time.

It all exploded at once.

Many scientists tried to understand and recreate the events of that fateful day. During the accident, 2.3 million gallons of syrup flooded the city. In fact, aerospace engineer Nicole Sharp conducted a study dedicated to the moment.

She didn’t use molasses.

The liquid Sharp included in the study, however, had a similar consistency. And when she poured corn syrup over a scaled model of the Boston, MA, town, the results were horrifying.

The smaller scale seemed to only magnify the gravity of the flood.

According to Sharp, the molasses was about 1.5 times denser than water. Consequently, the actual molasses “would have moved as a gravity current, much like a mudslide, avalanche, or lava flow.”

The weather that day only made the problem worse.

The initial flood continued for about two blocks since it was an unseasonably warm day for winter. However, that night when temperatures dropped. the molasses became more and more viscous.

There’s a reason the molasses affected so many people.

Due to the warm weather, most of the workers at the Boston, MA, factories decided to eat lunch outside. Many other residents around the city followed suit. Consequently, they were directly in the path of the molasses. Unfortunately, almost all of the distillery tank workers lost their lives because of the flood.

The brown wave was forceful enough to upend concrete structures.

In fact, multiple buildings fell down in 1919 because of the momentum. The structures even trapped Massachusetts citizens who were trying to flee. As the molasses slowed down, the residents got stuck in the liquid.

The molasses got everywhere.

The liquid syrup seeped into every crevice of the city. According to author and historian Stephen Puleo, it ran onto “subways, payphones, and even in the troughs provided curbside to the cities horses.”

And that’s not all.

There was so much molasses that the entirety of Boston Harbor turned brown.

Eyewitness Reports Gave Chilling Details About The Bizarre Event.

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For much of the event, the Boston citizens felt confused and ambushed. Apparently, most people had no idea what was even happening. Those first few moments of the accident offered a chilling depiction of a city in complete chaos.

Local newspapers gave a terrifying look at those first few moments before tragedy struck.

“Once the low, rumbling sound was heard no one had a chance to escape,” the Boston Globe reported. It was also as if, “the buildings seemed to cringe up as though they were made of pasteboard.”

Some say the entire North End shook.

It felt like a violent earthquake made its way to the east coast. According to H.P. Palmer, an accountant at the electric freight plant, he started to hear a rumble.

The sound was hardly the worst part.

Palmer went on to share that “within a minute, a huge stream of molasses began to run through the various streets and passageways, filling every section for two blocks.”

Emergency responders tried their best to help.

The Boston Globe reported that, “police and fireman who were near plunged through the great streams of heavy liquid, eager to give aid as best they could.”

Civilians tried to help their neighbors as well.

A local woman told the Globe:

I know there were people in the house and I ran into the street and called for help. Soon sailors and other people came running and I went back into my own house… They were hollering and crying.

Several People Lost Their Lives During The Accident

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The molasses was about a foot deep in some areas. And in total, 21 people lost their lives. They suffered from asphyxiation in the hours following the tragedy.

Everyone in the town suffered.

Moreover, around 150 people endured significant injuries. And the financial losses were not insignificant.

Rescue efforts were somewhat futile.

Many scientists speculated that the life-saving attempts would have been more effective if the accident had taken place in July. Apparently, during that time of year, the molasses would’ve spread out more, becoming thinner.

And a thinner consistency would have been more manageable.

The colder weather kept the molasses thick and heavy. Also, there was virtually no way for responders to prepare for such a bizarre event.

It took a total of four days for everyone to receive help.

Police, firemen, and other residents worked tirelessly for four long days to offer relief efforts. They wanted everyone to be released from the molasses as quickly as possible.

But it wasn’t easy.

The syrup took on a quicksand-like quality. Unfortunately, many people were maimed when they were dragged from the muck.

The process was so slow that Boston newspapers misreported the total casualty count.

All-in-all, the damage to buildings, many of which cascaded into the Boston Harbor, equaled more than $100 million dollars (adjusted for inflation). The accident is still recognized as one of the most lethal in the city’s history.

The cleanup took months.

After the rescue efforts concluded, the near-impossible task of cleaning up started. Indeed, the syrup froze to streets and buildings because of the frigid winter temperatures.

It couldn’t be left there, though.

If the Massachusetts team had waited for the molasses to thaw naturally, they likely would have developed dangerous bacteria. The first team of cleaners tried to wash the molasses away with water from the city’s fire hydrants.

Finally, a firefighter came up with a brilliant alternative.

According to historian Stephen Puleo, the firefighter, who was also considered a local hero suggested using saltwater instead. The brine would help cut the sugar.

And his idea worked.

To wash Boston, MA, clean, the people flushed millions of gallons of saltwater through the streets.

What Went Wrong?


As it turns out, the accident was completely preventable. In fact, the tank that was initially owned by the Purity Distilling Company never seemed to be perfectly operational.

And that’s where the problem began.

According to multiple reports, the vessel had leaks from the beginning. Plus, it measured 50 feet tall and 90 feet wide. The size was yet another safety hazard.

Employees at Purity Distilling had misgivings from the start.

Many of them tried to have the tank fixed. However, the company apparently refused to make any adjustments. Things were left to slowly fester.

The distillery owners continuously tried to cover up the leaks.

They didn’t fix the root of the problem. Instead, they allegedly painted the tank brown to make it look more like the molasses that spilled out. Eventually, the leak became so commonplace in the neighborhood that Boston children lined up in the street to fill cans with free molasses.

The tank should’ve never been there in the first place.

The tank was put much closer to the city than was common or safe. And at the time, the North End neighborhood residents were mostly Italian immigrants.

In fact, about 40,000 residents in the area were immigrants.

Not everyone had U.S. citizen rights, so they couldn’t vote. Consequently, the residents had no power to stop the tank from being located so close to their neighborhood.

The tank raised political questions.

According to historian Stephen Puleo, the construction clearly underlined the political climate and hierarchy in Boston, MA. He said the “had been leaking from day one.” But no one in power seemed to care.

Why did no one fix it?

Allegedly, many residents did report a problem. And the whole town recognized the molasses tank’s leak. However, no one of power or influence reported the problem, so it went unchecked and unfixed.

The Aftermath

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The investigation quickly highlighted Purity Distilling’s blatant lack of care, and chaos ensued after the revelation. Reports proved that the man who supervised the construction of the faulty tank not only lacked the technical training necessary to do the job. He also struggled to read.

That was especially dangerous for his line of work.

Moreover, no engineers or architects oversaw or consult on the structure which was a rarity for a build so large.

The company, however, seemingly didn’t want to accept blame.

At the time, though, the theory was somewhat plausible.

Indeed, radical anarchist groups were rather common in the early 1990s. In Boston, MA, alone, explosive tactics were used in 40 other incidents in the year leading up to the molasses flood.

People loved to blow stuff up, apparently.

Anarchists had also attacked another USIA facility in New York a few years before 1919. But the court case that ensued was just as bizarre as the accident itself.

The Courtroom Battle

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Indeed, the legal proceedings after the Molasses Flood were long and arduous. In total, it took more than five years to gather and examine all of the evidence.

And the opposing parties barely reached a consensus even then.

After a grueling trial, the court ruled that no act of sabotage had taken place, though. It was determined that a structural failure on behalf of the company was the sole cause of the explosion.

And the company did make a huge mistake.

During the course of the investigation, analysts discovered that two days before the explosion, the tank’s temperature was only 2° F. However, by the date of the accident, January 15, the temperature had skyrocketed to 40° F.

That’s not the worst of it.

The pressure in the tank increased because of the temperature. And to make matters worse, a new delivery of warm molasses was added to the cold molasses that had been there for weeks.

Does that matter?

Yes, it matters a lot. Mixing substances with two drastically different temperatures produced a gas that added to the pressure already building inside the molasses tank.

A Change For The Better

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Unfortunately, it wasn’t a lack of science that caused the Molasses Flood of 1919. It was a lack of care. The accident seemingly only happened because the company cut corners during the tank-construction process. The USIA was prompted to pay $15 million dollars in restitution for the accident after the court’s ruling.

People felt the ramifications around the country.

The accident and subsequent investigation resulted in more history-making changes. For the first time, the legal system held a business physically responsible for unsafe structures.

Indeed, the decision set a precedent.

Architect William J. Hirsch Jr., commented on the ruling saying, “accountability in construction was born.”

After the ruling, things began to change.

Shortly after the court’s decision, the Boston Building Department started requiring architects and engineers to include a signature and calculations about the building plans before construction started. Soon, the requirement reverberated across America and became standard practice.

Then it became law.

It wasn’t long before all locales in the United States created laws that required engineers and architects to have professional certifications. Beforehand, showing proof of certification was relatively uncommon.

Most companies winged it.

When constructing new structures, the builders rarely followed any safety protocols. So once the new law took effect things changed drastically.

No longer, could throwing a coat of paint on something make it “safe.”

Also, for a state or municipality to grant a building permit, they had to run the plans by a registered engineer who could give an official seal of approval on the project.

A hard-to-believe story with a huge effect.

It was certainly a weird and tragic accident. But the molasses flood helped to usher in a new level of construction around the country.

Practices were standardized and held to higher levels of competence.

From the devastation came a new code of conduct that is still in place today. Though unfortunate, the Great Molasses Flood helped prevent other factory oversights and horrible accidents.