00:00 On January 15, 1919, a storage tank filled with over 2 million gallons of molasses burst in Boston, killing 21 people and injuring 150 more.

01:46 In 1919, a storage tank filled with molasses burst in Boston, causing a deadly flood, and molasses was used as a principal source of sugar for the production of alcohol.

03:23 The storage tank for molasses in Boston was poorly designed and tested, with inadequate steel, improper installation of rivets, and a lack of proper testing, leading to immediate leaks and the need to paint the tank to hide them.

04:56 Molasses is a non-Newtonian fluid that becomes less viscous and flows more easily under pressure and when heated, which is important for understanding the events of the Great Molasses Flood.

06:37 A ship transferred over 600,000 gallons of heated molasses to the tank, almost completely filling it, and a warm front descended on Boston, causing the previously cold molasses to expand and create enough pressure to cause the tank to fail catastrophically, resulting in a wave of molasses that traveled at 35 miles per hour and had the explosive force of 850 sticks of dynamite.

08:13 The molasses flood caused buildings and elevated railways to collapse, and the viscosity of the molasses increased once it was exposed to the outside air, making it difficult for people to escape; the death toll eventually reached 21 and the cleanup was challenging, with molasses staining buildings and Boston Harbor for months.

09:47 The company responsible for the molasses flood was found guilty of negligence and had to pay $628,000 in damages; the flood remains the second worst disaster in the history of Boston.