The molasses tank was a disaster waiting to happen. Built in 1915 by the Purity Distilling Company, the 50-foot-tall, 90-foot-diameter steel tank was constructed hastily to meet wartime demand for alcohol production. The tank leaked so badly that children would collect the molasses seeping from its seams. The owner painted it brown to hide the leaks rather than fixing them.

On January 15, the tank was nearly full - 2.3 million gallons of molasses recently delivered from Puerto Rico. The temperature had risen from near zero to above 40 degrees Fahrenheit over two days, warming the molasses and increasing pressure. The poorly constructed tank couldn't hold.

When the tank failed, it failed completely. Steel plates ripped apart. Rivets shot out like bullets. A wave of molasses 25 feet high and 160 feet wide crashed through the Commercial Street area of the North End. The wave traveled at 35 miles per hour initially, faster than anyone could run.

The elevated railway structure was knocked off its supports. A fire station was pushed off its foundation. Houses were swept from their pilings. The steel tank itself was blown apart, pieces of it slicing through buildings. Those caught in the wave couldn't escape; molasses is heavy and viscous, trapping victims as effectively as quicksand.

Rescuers faced unique challenges. The molasses was waist-deep in some areas, making movement nearly impossible. It trapped victims in debris and filled their lungs as they struggled. The cold weather slowed the flow but also made rescue more difficult as the molasses thickened.

The USS Nantucket, moored nearby, sent 116 sailors to help. Nurses and doctors waded through the sticky mess. Rescuers used saws to cut through collapsed buildings while victims remained trapped in hardening molasses. Bodies were recovered for weeks, and the last victim wasn't found until four months later.

The disaster led to one of the first class-action lawsuits in Massachusetts history. Survivors and families of victims sued the United States Industrial Alcohol Company (Purity Distilling's parent company). The company's defense was creative: they claimed the tank had been bombed by anarchists.

The case took six years to resolve. Investigators found no evidence of sabotage but extensive evidence of negligent construction. The tank had never been properly tested. The steel was too thin. The rivets were insufficient. The company was found liable and paid nearly $1 million in damages - the equivalent of over $15 million today.

The Boston Molasses Disaster led to lasting changes in building regulations. Engineers were now required to certify structural plans. Inspections became mandatory. The disaster demonstrated that industrial negligence could have catastrophic consequences and that companies could be held legally responsible.

The cleanup took months. The harbor ran brown with molasses for weeks. Residents reported smelling molasses on hot summer days for decades. The North End Paving Company eventually paved over the area. Today, a small plaque marks the site. Old-timers insist they can still smell molasses on warm days - though this may be more legend than fact. What's certain is that Boston learned, in the strangest possible way, that even sweetness can kill.