On this day in history, just after noon, a massive tank holding some 26 million pounds of Puerto Rican molasses burst apart at the United States Industrial Alcohol Company (USIA) in Boston. Suddenly, a fifteen-foot wave of molasses moving at upwards of 35 miles per hour rushed through Boston’s North End, killing 21, injuring 150, doing $100 million in today’s dollars worth of damage, and necessitating a clean-up requiring 80,000 man-hours.
The company claimed anarchists must have blown up the tank, but subsequent investigations revealed that shoddy workmanship was responsible. The company had been in such a hurry to get the tank built back in 1915 that it didn’t even hire an engineer or architect. The overseer of the work couldn’t even read a blueprint. Nearby residents had reported leaks since the tank was put into use, but the company just painted the tank brown so the leaks would be less noticeable.
USIA soon found itself named as the defendant in 125 lawsuits. The Massachusetts Superior Court appointed an auditor who would hear the evidence and report back on the cause of the disaster. After nearly six years of hearing testimony, he concluded that there was no evidence to support the company’s theory of anarchist saboteurs. Rather, the “factor of safety” in the tank’s construction and inspection had been woefully low. USIA was found liable for the damage and made to pay around $7,000 to the family of each victim.
The case helped influence states to pass laws requiring that engineers and architects inspect and approve plans for major construction projects.