The Great Molasses Flood of 1919


Yes, you read that right. Back on January 15, 1919 an (unnatural) disaster occurred that seems to be ripped straight from the bible. A wave of molasses coursed through the streets of Boston, Massachusetts at an estimated 35 miles per hour.

The rushing dark goop overwhelmed crowds of pedestrians, killing 21 people and injuring another 150. To this day, Boston residents claim that the area still smells of molasses on hot summer afternoons.

So Who Let the Molasses Out?

At roughly 12:30 pm, a massive molasses tank, measuring 50 feet tall by 90 feet in diameter, at the Purity Distilling Company collapsed.

2.3 million gallons of molasses erupted out of the tank and into the North End neighborhood of Boston. Witnesses claim to have heard a “thunderclap-like bang!“, rumbles, roars, and even a machine gun-like sound as rivets rapidly shot out of the tank.

As the molasses traveled down the street, it formed a wave measuring 25 feet at its highest point. Nearby buildings were lifted off of their foundations and crushed beneath the weight of the substance.

Waist-deep (estimated 2-3 feet high) molasses covered the street, swirling and bubbling around the wreckage. A truck was even hurled into Boston Harbor.

The Sticky Aftermath

Under the orders of Lieutenant Commander H.J. Copeland from the USS Nantucket, 116 naval cadets ran from their ship docked nearby in order to help.

Unclear on exactly what to do, the cadets tried to simply keep on-lookers from getting in the way of rescuers that retrieved survivors trapped in the muck.

Soon after, members of the Boston Police Department, Army, Red Cross, and the Navy arrived to help. There were so many victims that make-shift field hospitals were established in nearby buildings.

North End residents filed one of the first class-action lawsuits in Massachusetts against the United States Industrial Alcohol Company (USIA), which had recently purchased Purity Distilling in 1917.

USIA attorneys futilely claimed that anarchists were responsible for blowing up the molasses tank, not negligence by the company.

Ultimately a court-appointed auditor found the USIA responsible for the disaster and ordered the company to pay out $600,000 in out-of-court settlements.

Cleaning Up the Mess

Crews on the ground used salt water pumped in from a nearby fireboat to wash the molasses away as well as sand to absorb what the hoses couldn’t clean.

Cleanup efforts expected to last only days stretched into several weeks with more than 300 individuals participating. However the molasses didn’t stay contained in the North End neighborhood.

People working in clean-up and rescue crews tracked molasses all over town, on subway platforms, inside trains, on to pay phones, and even inside homes.

The Cause of the Calamity

Several key factors caused the catastrophic tank failure:

  1. Due to the fermentation process taking place inside the tank, the internal pressure may have increased considerably.
  2. The local air temperature quickly rose from 2 to 41 °F over the previous day, possibly causing internal tank pressure to further rise.
  3. The tank was poorly constructed and incorrectly tested for structural failures. The site of the initial failure and crack was a manhole cover at the bottom of the cylindrical tank. In addition, the steel lacked manganese (making it more brittle) and was half as thick as it needed to be for the size of the structure.

Even though the area was thoroughly cleaned, the effects of The Great Molasses Flood lingered for years.

Edwards Park, an engineer who studied the area in 2015 said it best, “Everything a Bostonian touched was sticky.”