Boston Molasses Disaster – 1919

The Purity Distilling Company was an alcohol manufacturer based in the North End area of Boston, Massachusetts. A key ingredient of their industrial process was molasses, the syrupy by-product of sugar processing that served as a domestic sweetener and could be fermented to produce rum or (in Purity’s case) industrial ethyl alcohol. January 15 1919 was an unusually warm day.

Purity’s vast crude molasses storage tank at 529 Commercial Street was brimming with some 8.7 million litres (2.3 million US gallons) of molasses. The precise cause of what happened next was never established. It was probably a combination of factors – the hot day encouraging internal fermentation, a poorly maintained cast-iron tank and a stress crack near its base that had been overpainted rather than repaired.

Whatever the cause, there is no argument about the event itself. At 12.40 the 15 m (50 ft) tall tank fractured with a rumble, accompanied by the machine-gun popping of exploding rivets. The ground shook and a wave of molasses up to 4.5 m (15 ft) high engulfed the surrounding area, moving at an awe-inspiring 55 kph (35 mph) – a sticky tsunami that flattened buildings, invaded a fire station, tossed a train off the tracks and demolished bridges. When its energy was finally spent, several city blocks were flooded to a depth of 1 m (3 ft).

Rescue efforts were a nightmare, as clinging molasses hampered attempts to pull out the injured and recover the dead. A makeshift hospital was set up to treat the wounded as they emerged and it took four days – working day and night – to comb through the disaster scene. The last two bodies were so solidly glazed with molasses that they were never identified. The subsequent clean up required over 3,600 arduous man-days. Purity’s owners eventually paid out $600,000 in compensation.

When was the Boston Molasses Disaster: January 15 1919

Where was the Boston Molasses Disaster: Boston, Massachusetts, USA

What was the Boston Molasses Disaster: 21 dead (plus around 150 seriously injured).

You should know: It may be folklore coupled with autosuggestion, but locals living around the site of the great molasses flood (now a community baseball field) insist that it’s still possible to smell the unmistakable sweet odour of molasses on hot days.