The Great Molasses Flood
On January 15, 1919, in Boston’s North End, a massive storage tank at the Purity Distilling Company facility burst, releasing a wave of molasses that killed 21 people and injured 150. The tank, used to offload molasses from ships and store it for later transfer to an ethanol plant in Cambridge, collapsed around 12:30 p.m. Temperatures had risen rapidly from the previous days’ cold, and a fresh shipment of warm molasses had just been added. The older, colder molasses inside may have expanded from the heat, causing the tank to rupture. Witnesses reported a ground-shaking roar, a sound like a thunderclap or machine gun as rivets shot out, and a long rumble similar to a passing elevated train.
Molasses is about 40% denser than water, giving the wave immense force. It surged at speeds high enough to knock a streetcar off its tracks, sweep people and debris into the harbor, and demolish buildings. Because molasses is a non-Newtonian fluid, it thinned and flowed quickly under pressure, then became thick and sticky in the cold, trapping victims and making rescue difficult. The flood reached depths of several blocks, and the cleanup took two weeks. For decades afterward, residents said the area smelled of molasses on hot summer days.
Rescuers included 116 cadets from a nearby training ship, along with police, Red Cross nurses, and Army and Navy personnel. Some nurses waded into the molasses, while others set up a makeshift hospital. The search for victims lasted four days; some bodies were found months later in Boston Harbor. A class-action lawsuit against the company that owned the tank—one of the first such suits in Massachusetts—found the company responsible after three years of investigation, rejecting its claim that anarchists had caused the explosion.
- Location
- North End, Boston, Massachusetts
- Deaths
- 21
- Wave height
- 25 feet (8 meters)
- Wave speed
- 35 miles per hour (56 kilometers per hour)
Lore & Background
The Great Molasses Flood occurred on January 15, 1919, in Boston’s North End, when a large storage tank at the Purity Distilling Company facility on Commercial Street burst. The tank, used to offload molasses from ships for later transfer to a Cambridge ethanol plant, collapsed around 12:30 p.m. after a ship had delivered a fresh, warmed load the previous day. Rising temperatures that day may have caused thermal expansion of the older, colder molasses inside, triggering the rupture. Witnesses reported a ground-shaking roar, a sound like a thunderclap or machine-gun fire as rivets shot out, and a long rumble similar to an elevated train. The resulting wave of molasses, which is about 40% denser than water, surged up to 25 feet high and moved at an estimated 35 miles per hour. Its force drove steel tank panels into elevated railway girders, tipped a streetcar off its tracks, swept buildings off their foundations, and hurled a truck into the harbor. The molasses, a non-Newtonian fluid, thinned under stress and flowed quickly initially, then became viscous in the cold, trapping victims. The flood killed 21 people and several horses, injured about 150, and caused coughing fits among survivors. Cleanup took weeks, using salt water and sand, and the harbor remained brown with molasses into summer. For decades afterward, residents said the area still smelled of molasses on hot days.
Reader's Guide
The Great Molasses Flood is significant as a landmark disaster in industrial and urban history, illustrating the dangers of poor construction and inadequate safety testing. The inquiry revealed that Arthur Jell, the company's treasurer, neglected basic safety tests and ignored warning signs like groaning noises. The event also occurred as the company was trying to out-race Prohibition, as the Eighteenth Amendment was ratified the next day. The class-action lawsuit against USIA is considered a milestone in the development of modern corporate regulation, setting a precedent for holding companies accountable for negligence. The disaster's unusual nature—a wave of molasses—entered local folklore, and its legacy includes lasting changes in industrial safety standards and legal liability.
Did You Know?
- The molasses wave was 25 feet high and moved at 35 miles per hour.
- The tank had been filled to capacity only eight times since it was built, putting cyclical stress on its walls.
- The class-action lawsuit against the United States Industrial Alcohol Company is considered a milestone in modern corporate regulation.
- Residents reported that the area still smelled of molasses on hot summer days for decades after the disaster.
Common Misconceptions (Editorial)
- Some believe the tank was destroyed by anarchists, as the company initially claimed, but a court-appointed auditor found the United States Industrial Alcohol Company responsible after three years of hearings. - The molasses wave is often exaggerated in size and speed, but records confirm it was 25 feet high and traveled at 35 miles per hour—still devastating, but not mythical in scale.
Why It Matters (Editorial)
The Great Molasses Flood endures as a stark reminder that industrial negligence can turn everyday materials into lethal forces. It also stands as a landmark case in corporate accountability, proving that no company is above the law when their failures cause mass tragedy.
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