On January 15, 1919, a massive storage tank containing over two million gallons of molasses burst in Boston's North End, killing 21 people and injuring 150. While initial company claims blamed anarchists, forensic engineering later revealed catastrophic metallurgical flaws and reckless construction practices. Built in 1915 by the Industrial Alcohol Company, the 50-foot-high tank was constructed hastily without proper engineering oversight or hydrostatic safety tests.
The steel plates used were dangerously thin and lacked sufficient manganese, making the metal highly susceptible to brittle fracture in cold temperatures. On the day of the disaster, unseasonably warm weather caused the cold molasses inside to expand, dramatically increasing internal stress. Years prior to the collapse, local residents had reported persistent structural warning signs.
The tank frequently groaned and creaked under pressure, and molasses leaked so profusely from the riveted seams that neighborhood children collected it in cans. Rather than reinforcing the structure, the owners simply painted the steel brown to disguise the leaks. The eventual structural failure served as a landmark case, leading to mandatory engineering certifications and stricter building codes across the United States.