The Great Molasses Flood of 1919

A Deluge of Negligence

On January 15, 1919, a bizarre and tragic disaster struck Boston's North End. Explore the story of the Great Molasses Flood, a catastrophe born from corporate greed that reshaped a community and changed American law forever.

Act I: A Community in the Shadow

To understand the disaster, one must first understand the community that lived beside the colossal tank. Boston's North End in 1919 was a vibrant, densely populated immigrant enclave—a community with a rich culture but little political power, making it a place where industrial hazards could be placed with impunity.

Boston's "Little Italy"

By 1919, the North End was the heart of Boston's Italian-American life. The vast majority of residents were recent immigrants and their children, creating a tight-knit but isolated community. This demographic reality played a crucial role in both the lead-up to the disaster and its aftermath.

~90%

Of North End residents were Italian-American

Only 25%

Of Boston's Italians were citizens with voting rights

Act II: Anatomy of a Failure

The flood was not an accident; it was an inevitability. A forensic look at the molasses tank reveals a cascade of catastrophic failures in design, construction, and oversight, driven by a corporate culture that prioritized profit over safety. Click on each point in the timeline to uncover the layers of negligence.

A Blueprint for Disaster

The project was rushed and overseen by a company treasurer with no engineering experience. No certified engineer or architect ever reviewed the plans, a foundational error that guaranteed a flawed design from the start.

No Engineer on Record

USIA's treasurer, Arthur Jell, managed the project without any professional engineering oversight.

Dangerously Thin Steel

The steel plates were half as thick as required, unable to withstand the pressure of 2.3 million gallons of molasses.

Insufficient Rivets

The joints were critically flawed, with too few rivets to hold the plates together under stress.

No Safety Testing

A standard water test to check for leaks was skipped to save time and money, putting the tank into service untested.

Warnings Ignored

For years, the tank audibly groaned and leaked. Residents collected dripping molasses, while employee warnings were dismissed.

The Final Straw

A new, warm shipment of molasses was pumped into the cold tank, causing thermal expansion and adding the final, fatal stress.

Act III: The Deluge

At 12:40 PM, the tank ruptured. In an instant, a bizarre tsunami of industrial sludge was unleashed. The wave was a terrifying physical paradox: moving with the force of a locomotive yet as inescapable as quicksand.

0

Feet High

The initial wave was taller than a two-story building.

0

Miles Per Hour

The molasses moved at the speed of a galloping horse.

0

Tons of Molasses

An immense weight that obliterated everything in its path.

Path of Destruction

The wave tore through Commercial Street, reducing buildings to splinters and twisting the steel girders of the elevated railway. Firehouse 31 was knocked from its foundation, trapping firefighters inside. The entire area was left submerged in a sticky morass two to three feet deep.

Act IV: The Human Cost

The disaster claimed 21 lives and injured 150 people. The victims were laborers, children, a firefighter, and homemakers—a cross-section of the working-class community whose lives were extinguished in an instant. Explore the data to see who was most affected, and read their stories.

In Memoriam

Click on a bar in the chart to filter the list of victims by their role in the community. Each name represents a life cut short by the flood.

Act V: A Landmark Legal Battle & Lasting Legacy

The flood triggered one of the first class-action lawsuits in Massachusetts history. The six-year legal battle pitted a community of immigrants against a powerful corporation and set a crucial precedent for corporate accountability in America.

The People vs. U.S. Industrial Alcohol

Argument: Corporate Negligence

Led by attorney Damon Hall, the plaintiffs built a meticulous case based on scientific evidence. Expert testimony from an MIT professor proved the tank was structurally unsound from day one due to thin steel, poor riveting, and a complete lack of engineering oversight. They argued the disaster was not just foreseeable, but guaranteed.

The Verdict: Accountability

In 1925, the court found USIA fully liable, dismissing the sabotage theory. The company was ordered to pay the equivalent of nearly $10 million today, a landmark ruling that affirmed corporations could be held responsible for public safety.

The Enduring Legacy

The disaster was a catalyst for change. In its wake, Massachusetts and states across the country passed laws requiring certified engineers and architects to approve all major construction plans. The Great Molasses Flood, a bizarre and tragic event, ultimately helped build the foundations of modern regulatory oversight and made cities safer for everyone.

© 2025 An Interactive History. All data sourced from the historical record.