They were either knocked over and crushed or drowned in the goo. The flood claimed 21 lives, and another 150 people suffered injuries. Any flood would have been disastrous, but the viscous nature of molasses made rescue attempts even trickier. Medics and police officers arrived on the scene quickly but had to slog through waist-deep goo to reach victims.
http://mentalfloss.com/article/27366/bostons-great-molasses-flood-1919
Boston's Great Molasses Flood of 1919. On January 15, 1919, Boston suffered one of history’s strangest disasters: a devastating flood of molasses. The “Great Molasses Flood” tore through the city's North End and deposited so much gooey residue that locals claimed they could still smell the molasses on warm days decades later.
http://mentalfloss.com/article/27366/bostons-great-molasses-flood-1919
How many people died in the great molasses flood of boston, ma.
http://www.chacha.com/question/how-many-people-died-in-the-great-molasses-flood-of-boston%2C-ma
On hot, summer days in one of the oldest neighborhoods in Boston, they say, a faint, sickeningly-sweet odor wafts up from cracks in the pavement -- the stench of 85-year-old molasses. THE DATE was January 15, 1919, a Wednesday. It was about half-past noon.
https://www.thoughtco.com/molasses-clocked-at-35-mph-in-january-3299457
Magazine looks at science behind 1919 molasses disaster. On January 15, 1919, 21 people died when a tank at the Purity Distilling Co. in the North End burst, spewing molasses everywhere. Shortly after noon on Jan. 15, 1919, Boston’s North End was shaken by the bursting of a giant iron tank atop the Purity Distilling Co. on Commercial Street.
https://www.bostonglobe.com/metro/2013/08/13/molasses-disaster-boston-north-end-showed-lethal-power-thick-substances/nbhChG332PTOLTAnd7L6DL/story.html
But on January 15, 1919, in Boston's North End, on a sunny, warm day, the molasses tank in the neighborhood blew. More than 2,300,000 gallons of molasses, weighing 13,000 tons, flowed down the street, uplifting houses, twisting railroad tracks and killing 21 people.
https://www.charlesbridge.com/products/the-great-molasses-flood
On January 15, 1919, 21 people died when a tank at the Purity Distilling Co. in the North End burst, spewing molasses everywhere. Globe Correspondent August 14, 2013. Shortly after noon on Jan. 15, 1919, Boston’s North End was shaken by the bursting of a giant iron tank atop the Purity Distilling Co. on Commercial Street.
https://www.bostonglobe.com/metro/2013/08/13/molasses-disaster-boston-north-end-showed-lethal-power-thick-substances/nbhChG332PTOLTAnd7L6DL/story.html
Modern downtown Boston with molasses flood area circled. At about 12:30 in the afternoon near Keany Square, at 529 Commercial Street, a molasses tank 50 ft (15 m) tall, 90 ft (27 m) in diameter, and containing as much as 2,300,000 US gal (8,700 m3), collapsed.
https://en.wikipedia.org/wiki/Boston_Molasses_Disaster
On January 15, 1919, a two-million-gallon holding tank filled with molasses exploded, flooding Boston's North End near the port. In all, 21 people died in the disaster, and around 50 were injured. The sticky flood swamped the area, and cleanup proved difficult until it was discovered that seawater seemed to break it up.
https://www.charlesbridge.com/products/the-great-molasses-flood
The Great Molasses Flood, also known as the Boston Molasses Disaster or the Great Boston Molasses Flood, occurred on January 15, 1919 in the North End neighborhood of Boston, Massachusetts. A large molasses storage tank burst and a wave of molasses rushed through the streets at an estimated 35 mph (56 km/h), killing 21 and injuring 150.
https://en.wikipedia.org/wiki/Boston_Molasses_Disaster
how many people died in the molasses flood
Twenty one  people died in the Molasses flood. There are 21 people died in the molasses flood.