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The Great Molasses Flood

A bizarre disaster struck one of America’s biggest cities 100 years ago.

January 7, 2019
By Amy Birnbaum

Jim McMahon/Mapman®

Imagine a river of thick, very sticky syrup rushing through a busy neighborhood. That’s what happened 100 years ago in Boston, Massachusetts, causing one of the strangest tragedies in U.S. history.

It all began near Boston Harbor with a 50-foot-tall steel tank filled with more than
2 million gallons of molasses. The brown syrup is often used in baking. But the molasses in the tank on Boston’s Commercial Street wasn’t intended to be used in cookies and cakes. Instead, it would be heated and turned into industrial alcohol, a liquid that was used to make explosives and other products.

But on January 15, 1919, just after noon, people in the neighborhood heard a sound that some thought was gunfire. It was actually the rivets, or metal bolts, that held the tank together beginning to pop out. Suddenly, the tank unleashed a 30-foot-high wave of molasses.

“The molasses moved very fast and destroyed everything in its path,” says Stephen Puleo, the author of the book Dark Tide: The Great Boston Molasses Flood of 1919. “Very few people outran it.”

Those who got caught in the thick, sticky flood found it hard to escape. Sadly, 21 people drowned, and 150 more were injured. The force of the wave also knocked down buildings and badly damaged an elevated train track.

Cleaning up the gooey mess wasn’t easy. The molasses had thickened in the cold winter air. After trying different methods, firefighters found that salt water helped break up the molasses. They used water from Boston Harbor to finally wash it away.

The Boston Globe via Getty Images

After the tank of molasses burst, police, firefighters, and other rescuers rushed to help people injured by the flood.

After the Disaster

How could something so terrible have happened? It turned out that the disaster was caused by shoddy construction. The owner of the tank, a company called United States Industrial Alcohol (USIA), had rushed to build it. The steel walls of the tank were too thin to hold so much of the brown syrup.

The tank leaked almost from the day it was first filled in 1915. It rumbled and groaned as it strained to hold in the molasses.

People living near the tank worried that it was unsafe. But there wasn’t much they could do. USIA was a big company, and the people who lived in the tank’s shadow were mostly poor immigrants. They feared that no one would listen to their concerns.

As the years passed, the leaks and the rumblings from the tank continued. On that January day in 1919, the tank finally broke apart, releasing a deadly flood.

The leaders of USIA said the disaster was not their fault. But experts spoke to residents and looked at what was left of the tank. They knew the company was responsible. After a long trial, a court ruled that USIA had been careless. The company was ordered to pay $628,000 (about $9 million today) to the families of the flood victims.

In the years after the flood, Massachusetts passed laws with tougher requirements for new building projects. Those safety standards were widely adopted in other states.

“The standards we have today were put in place in Boston and Massachusetts and then rippled across the country,” says Puleo.

1. What text structure does the article mostly follow? How do you know?

2. What signs showed that the tank might be unsafe? Why didn’t more people speak up?

3. What happened in the years after the flood?

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