January 15, 1919, started as an unseasonably warm winter day in Boston’s North End. The temperature had risen to 40°F after weeks of bitter cold. By mid-afternoon, this pleasant weather would become a contributing factor to one of the city’s most bizarre disasters: a flood of molasses that killed 21 people, injured 150, and caused millions of dollars in damage.
The Tank
The Purity Distilling Company operated a massive storage tank at 529 Commercial Street in Boston’s North End, a densely populated immigrant neighborhood. The tank stood 50 feet tall and 90 feet in diameter, with the capacity to hold 2.3 million gallons of molasses.
The molasses arrived by ship from the Caribbean and was stored in the tank before being distilled into industrial alcohol, used in munitions production during World War I. The tank had been hastily constructed in late 1915 to meet wartime demand, with construction completed in just six months.
From the beginning, the tank had problems. It leaked so badly that the company painted it brown to hide the seeping molasses. Local children would collect the leaked molasses in cans. Residents complained about rumbling sounds when the tank was filled, and the structure visibly trembled when full.
Arthur Jell, the company’s treasurer, allegedly ignored these warning signs. One employee later testified that he had expressed concerns about the tank’s safety, but his warnings were dismissed.
The Collapse
At approximately 12:30 PM on January 15, 1919, the tank catastrophically failed. The structure burst apart with a sound witnesses compared to machine gun fire or a passing elevated train. Rivets popped like bullets, one allegedly killing a person on the street.
The tank disintegrated, releasing its entire contents in a matter of seconds. Two-point-three million gallons of molasses—weighing approximately 13,000 tons—rushed into the streets in a wave initially estimated at 25 feet high.
The wave moved at approximately 35 miles per hour, faster than a person could run. The thick, sticky substance was far more dangerous than water of similar volume. Its viscosity meant it clung to victims, making escape nearly impossible. The sheer weight and force of the wave demolished buildings, knocked trains off their elevated tracks, and buckled steel support beams.
Victims and Devastation
Twenty-one people lost their lives in the flood:
- Patrick Breen, a laborer, was found two weeks later under debris
- Bridget Clougherty died in her home, which was destroyed by the wave
- Stephen Clougherty, age 8, a victim while playing in the street
- John Callahan, an employee of the city paving department
- Maria Di Stasio, age 10, was caught in the wave on her way home
- William Duffy, a teamster, died while working
- Peter Francis, a blacksmith, was killed in his shop
- Flaminio Gallerani, another laborer working nearby
- Pasquale Iantosca, age 10, collecting firewood from broken crates
- James Kenneally, laborer
- Eric Laird, an engine driver for Boston Elevated Railway
- George Layhe, teamster
- James Lennon, teamster
- Ralph Martin, teamster
- James McMullen, laborer
- Cesar Nicolo, another express driver
- Thomas Noonan, longshoreman
- Peter Shaughnessy, an express driver
- John Seiberlich, blacksmith
- Michael Sinnott, fireman
- Martin Tracey, driver
Additionally, 150 people were injured, some severely. Horses—vital for transportation and commerce in 1919—were also killed, trapped in the sticky mass with no hope of escape.
The Immediate Aftermath
The North End became a disaster zone. Molasses covered everything, making rescue and recovery efforts extraordinarily difficult. Rescuers waded through waist-deep molasses, searching for victims. The sticky substance made every movement exhausting.
The flood destroyed the Atlantic Avenue Elevated Railway’s support beams, severely damaged several buildings, and turned streets into impassable morasses. Fire boats pumped saltwater from the harbor to wash away the molasses, but this simply spread it further. The harbor turned brown.
The cleanup took weeks. Workers used sand and saltwater, but molasses penetrated wood, seeped into basements, and invaded the sewers. Residents reported that the neighborhood smelled of molasses for decades. Some claimed they could still detect the odor in hot summer weather into the 1970s.
Legal Aftermath
The disaster triggered one of the longest and most complex legal battles in Massachusetts history. Families of victims and property owners filed 119 lawsuits seeking nearly $1 million in damages against the United States Industrial Alcohol Company (USIA), which owned Purity Distilling.
The company initially tried to blame anarchists, claiming that the tank had been bombed. This theory played on contemporary fears—anarchist bombings had occurred in the U.S., and Boston had a reputation as a center of radical activity. However, investigators found no evidence of sabotage.
The case lasted six years. The court heard from 3,000 witnesses, examined 1,500 exhibits, and produced 6,000 pages of testimony. Expert witnesses from both sides analyzed the tank’s construction and the molasses’s properties.
In 1925, Auditor Hugh W. Ogden found USIA responsible. His report concluded that the tank was structurally insufficient for its contents and that the company had been negligent in its construction and maintenance. USIA paid out approximately $600,000 in settlements (equivalent to about $9 million today), though many victims and their families felt this was inadequate compensation.
Scientific Investigation
Modern engineering analysis has revealed the technical failures that caused the disaster. The tank’s steel walls were only half as thick as they should have been for the load they carried. The rivets were of insufficient quality and poorly installed. Most critically, the design completely failed to account for the properties of molasses.
Molasses is a complex non-Newtonian fluid. Its viscosity decreases with temperature. When cold, it flows very slowly (hence the expression “slow as molasses in January”). But the unusually warm weather on January 15 had raised the molasses temperature, significantly decreasing its viscosity and increasing the pressure on the tank walls.
Furthermore, a fresh shipment of molasses had arrived just two days earlier, on January 13. This new molasses was warmer than the existing contents. Scientists now understand that this temperature difference could have created convection currents within the tank, further increasing stress on the structure.
The combination of a poorly constructed tank, maximum fill, warming temperature, and internal thermal dynamics created the perfect conditions for catastrophic failure.
Cultural Impact
The Great Molasses Flood entered Boston’s historical consciousness as both tragedy and oddity. The unusual nature of the disaster—a flood of molasses rather than water—has fascinated people for over a century.
The event has been referenced in numerous books, documentaries, and articles. It appears in urban legends about Boston still smelling like molasses on hot days. The site is now a park, and a small plaque commemorates the victims.
The disaster influenced industrial regulations. It demonstrated the need for stricter building codes, engineering oversight, and corporate accountability for industrial facilities. The lengthy legal case established precedents for proving corporate negligence in industrial disasters.
Lessons Learned
The molasses flood illustrates several enduring themes:
First, it shows the dangers of prioritizing speed and profit over safety. The tank was built quickly to meet wartime demand, with insufficient attention to engineering standards.
Second, it demonstrates how unusual material properties can create unexpected hazards. Molasses behaves differently than water, but the tank’s designers didn’t adequately account for these differences.
Third, it highlights the importance of listening to warnings. Multiple people had expressed concerns about the tank’s safety, but these concerns were ignored until disaster struck.
Finally, it reminds us that disaster can strike in unexpected ways. A tank of molasses seemed an unlikely source of catastrophe, yet it killed more people than many more “obvious” hazards.
Legacy
Today, the Great Molasses Flood is remembered as a quintessentially Boston disaster—bizarre, tragic, and ultimately a catalyst for positive change. It stands alongside other industrial disasters like the Triangle Shirtwaist Factory fire as an event that, through terrible loss, led to improved safety standards and greater corporate accountability.
The flood reminds us that engineering failures have human costs, that materials science matters, and that safety concerns should never be dismissed. It also serves as an unusual reminder that disaster can come in the most unexpected forms—even in a sweet, sticky wave flowing through city streets on an unseasonably warm January day.