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db history: The Boston Molasses Flood of 1919

This week marks the centenary of The Great Boston Molasses Flood, when millions of gallons of molasses meant for alcohol production flooded the streets causing havoc, destruction and death.

North End Docks, Boston, after the disaster

The disaster took place on 15 January 1919 at the Purity Distilling Company, a chemical firm that specialised in the production of ethanol for use in alcoholic beverages, medicine and ammunition.

The company’s storage facility was located in Boston’s North End neighbourhood, down by the waterfront near the harbour.

One of Purity’s biggest storage tanks, built in 1915, was 50 foot tall (15 metre) and 90ft in diameter, capable of holding 2.3 million US gallons (8.7m litres) of molasses.

On 15 January this tank was full, its contents waiting to be transferred to the distillery in Cambridge, Massachusetts, for processing.

Soon after midday the tank burst. Afterwards, those interviewed remembered an almighty noise, “a thunderclap” and a long rumble like a train accompanied by the machine-gun-like rattle of thousands of rivets popping.

The ground shook and there was a terrible roar as millions of gallons of sticky molasses rushed down the Commercial Street. Being one and a half times as dense as water the potential energy in the wave was enormous. It is estimated it picked up speeds of 35 miles per hour and at its peak was 25 ft (8m) high.

It buckled the girders of the nearby elevated railway, some standalone buildings were ripped apart and people and objects were picked up and flung about with contemptuous ease. As the wave subsided the molasses still stood waist deep in many places.

A report in the Boston Globe related: “Molasses, waist deep, covered the street and swirled and bubbled about the wreckage…. Here and there struggled a form—whether it was animal or human being was impossible to tell. Only an upheaval, a thrashing about in the sticky mass, showed where any life was…. Horses died like so many flies on sticky fly-paper. The more they struggled, the deeper in the mess they were ensnared. Human beings—men and women—suffered likewise.”

Twenty-one people were killed in the great rush, the oldest (Michael Sinnott) being 78 and the youngest being two children aged 10 (Pasquale Iantosca and Maria Di Stasio) and another 150 injured. Some had been swept into the harbour and were not found for some time, even up to four months after the event. Even after a four-day search and rescue effort, others were found drowned or suffocated when the molasses was cleared away but were so glazed with sugar they could barely be identified.

The clean-up took weeks, boats and engines pumping seawater onto the harbour front to wash the molasses away. The dock front was stained brown for months and the number of people involved in the clean up from around the city spread the substance around and people claimed everything in Boston became oddly sticky. The smell was also said to have lingered for years after the event. “The smell of molasses remained for decades a distinctive, unmistakable atmosphere of Boston,” claimed the journalist Edwards Park.

Residents and victims of the disaster brought a lawsuit against Purity Distilling’s parent company, the United States Industrial Alcohol Company, one of the first in Massachusetts.

Originally claiming the tank had been sabotaged by anarchists because of the company’s links to the arms industry, USIA eventually paid US$628,000 in damages (around $9m in 2018).

The reasons for the disaster are not entirely known but a likely scenario, widely accepted, states that the poor construction and maintenance of the tank and sustained overloading in the weeks and months leading up to the event caused a catastrophic failure of the tank’s superstructure.

Furthermore, warm molasses had been added to the tank two days before the disaster and the weather had warmed substantially from -17° centigrade to 5° (2° F to 41°) in the space of a few days.

This might have started some fermentation in the tank which would have raised the pressure and put an enormous strain on the supposed weak point – a fatigue crack near a manhole cover at the base of the tank.

Furthermore, the warmer molasses was considerably more liquid than it might otherwise have been, making it slicker and much quicker when it finally burst free of containment.

It has sometimes been claimed that USIA and Purity Distilling had ramped up production in the months leading up to the tragedy as they sough to sell and stockpile alcohol before the implementation of the 18th amendment – also known as Prohibition – which was ratified, in fact, on the following day (16 January).

The case bears many similarities to the London beer flood of 1814, when a similarly oversized but structurally weak tank burst its sides and sent a massive wave of around 1m gallons of porter beer down Tottenham Court Road, killing eight people.

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