Clichés tend to become clichés for a reason. “Slow as molasses” is generally an apt statement: molasses is highly viscous and therefore flows at a slow rate of speed. Comparing something slow to the movement of molasses is valid.
Except when the molasses is going thirty-five miles an hour.
Ninety years ago, Boston’s North End was the home of the city’s busiest center of commerce: the North End Paving Yard and the Commercial Street Wharf. Freighters from all over the world crowded against one another, taking on or discharging cargoes–livestock, tea, coffee, wool, raw materials for a hundred different trades; locomotives shunted freight cars to and from the wharf to deliver or receive goods from the ships. Stonecutters chipped and shaped pavement blocks in the Yard. Successive waves of immigrants had settled in the neighborhood, and the patter of stevedores and dockhands and blacksmiths and drivers varied from Italian to Irish. There was a lot of work to be had, and a lot of workers competing for it.
One of the landmarks of the North End waterfront was the United States Industrial Alcohol Company’s fifty-foot-high storage tank, holding the molasses the company used to distill its product. This tank, capable of holding over two million gallons of molasses, was used to store molasses from freight tankers before discharging it to railway tank cars for transportation to USIA’s distillation plant. It had been built in a tearing hurry during the month of December, 1915, after lengthy delays in negotiation regarding leasing the land for the tank site and securing permission for the construction. USIA needed the tank ready to accept a shipment of molasses by December 31, and by jingo it was completed in time.
It wasn’t tested to see how the construction held up, of course, because it would have taken days and dollars to fill it up with water: the individual responsible for the construction of the tank, Arthur P. Jell, happened to be the treasurer of USIA’s subsidiary Purity Distilling, and was well aware of the amount the company stood to lose if they wasted any time. Jell instructed that the tank should be filled with water to the level of six inches, enough to cover the joint at the base of the construction, and when this did not result in leaks he declared the tank safe for use.
In point of fact it leaked like an enuretic hamster. In February 1916, two months after completion, the tank was observed to be leaking molasses from its seams, dribbling the stuff in slow streams down the outside to pool around the base in quantities sufficient for children to come and scoop it up in pails. The leaks had been reported to the company, and Jell ordered the tank recaulked twice and painted brown to hide the leaks.
Stephen Puleo’s comprehensive book on the disaster, The Dark Tide, describes one employee, Isaac Gonzalez, as feeling the tank vibrate and hearing it groan every time a shipment of molasses was pumped in. According to Puleo, Gonzalez was deeply concerned about the tank’s structural integrity, and when he was warned after mentioning the leakage that voicing further complaints or concerns to management would get him fired, he took it upon himself to do what he could to lower the risk of disaster. This included sleeping in an office next to the tank so as to be able to sound an alarm in case of imminent rupture. On one of the nights he spent in the office by the tank, he received an anonymous phone call stating that the tank would be blown up with dynamite and everyone who worked there would be killed.
This last was more of a worrisome threat than might be imagined. At the time, USIA’s ethanol was being used in manufacturing munitions for the war in Europe; it was thought that the anti-war anarchists who had been operating in the area might target the plant. After that phone call Gonzalez no longer slept by the tank; however, Puleo’s book offers a vivid description of his nightly visits to the plant to secretly release molasses into the harbor and ease the pressure within the tank:
Working quickly, Isaac twisted open a valve and began releasing molasses into the harbor, and along with it any gasses that had built up inside the tank. After ten minutes, he closed and tightened the valve. He had no idea how many gallons of molasses had been dumped, and practically speaking knew it would make little difference in the overall capacity of the tank, which held over two million gallons when it was full. Isaac also knew that he would be fired, prosecuted, and most likely sent to jail if Mr. Jell ever found out about these late-night visits. But dumping the molasses helped clear his head and made him feel less helpless. (Puleo, p.5)
Over the next two years the tank continued to dribble molasses and make alarming groaning noises when the supply was pumped in, but nothing more. Most likely no single factor can be blamed for its disastrous failure: a combination of shoddy and rapid construction, lack of maintenance or safety oversight, freak temperature changes, and general bad luck was probably responsible.
The temperature on the 15th was forty-three degrees Fahrenheit, unseasonably warm for January; on the 12th it had been two degrees, on the 13th sixteen, and on the 14th it had jumped from sixteen to forty. Fermentation may have taken place within the tank as the temperature rose sharply, producing carbon dioxide and increasing the tank’s internal pressure beyond its structural limits. Whatever was responsible, the result was the same.
Half past noon on Wednesday, January 15, a low rumbling noise like a train passing by shook the ground, accompanied by a rapid staccato machine-gun roar as the tank rivets shot away from their plates and the bottom of the massive tank ruptured, spewing out approximately 2,300,000 gallons of molasses. The force of the escaping fluid split the remains of the tank in half.
In a 1965 article originally printed in Yankee Magazine, John Mason describes the first moments of the disaster:
[In] less time than it takes to tell it, molasses had filled the five-foot loading pit, and was creeping over the threshold of the warehouse door. The four loaded freight cars were washed like chips down the track. The half-loaded car was caught on the foaming crest of the eight-foot wave and, with unbelievable force, hurled through the corrugated iron walls of the terminal.
The freight house shook and shivered as the molasses outside, now five feet deep, pushed against the building. Then the doors and windows caved in, and a rushing-roaring river of molasses rolled like molten lava into the freight shed, knocking over the booths where freight clerks were checking their lists.
Like madmen they fought the on-rushing tide, trying to swim in the sticky stuff that sucked them down. Tons of freight—shoes, potatoes—barrels and boxes—tumbled and splashed on the frothy-foaming mass, now so heavy the floors gave way, letting tons of the stuff into the cellar. Down there the workers died like rats in a trap. Some tried to dash up the stairs but they slipped and fell—and disappeared.
As the fifty-eight-foot-high tank split wide open, more molasses poured out under a pressure of two tons per square foot. Men, women, children and animals were caught, hurled into the air, or dashed against freight cars only to fall back and sink from sight in the slowly moving mass.
Having wiped the freight house off the face of the Earth, the molasses lahar proceeded to take out part of the El support, destroying a section of track, knocked over a fire station, filled up a Public Works building, and turned a number of houses into gluey matchwood, moving at an estimated thirty-five miles per hour.* Twenty-one people died, either crushed to death or drowned in molasses–which if you stop to think about it is a peculiarly horrible way to die–and a hundred and fifty more were injured in the disaster. Two of the dead could not be identified, too battered and candied for recognition.
Unlike floods of, say, water, the molasses flood’s clean-up took weeks. Squirting water on the ankle-deep goo did nothing at all; firemen eventually had to use salt water to blast molasses from the streets and walls, washing it down into the harbor (which was brown and redolent of sugar for months). It took 87,000 man-hours to clean up the mess, and a further six years before the ensuing trial was completed and a report published. USIA, unsurprisingly, was found responsible for the disaster through an insufficient “factor of safety,” meaning they didn’t build the damn tank strong enough to hold its contents. Which Isaac Gonzalez pointed out to Arthur Jell in 1915.
Today the site of the tank has been turned into a playground, next to a park; there’s a small plaque at the entrance to the park commemorating the flood:
On January 15, 1919, a molasses tank at 529 Commercial Street exploded under pressure, killing 21 people. A 40-foot wave of molasses buckled the elevated railroad tracks, crushed buildings and inundated the neighborhood. Structural defects in the tank combined with unseasonably warm temperatures contributed to the disaster.
They say that on hot days you can still smell ninety-year-old molasses in the air. It’s still there, of course, in the joints between bricks, in the ground, in the earth. It’s the sweet smell of criminal negligence–less sickly than trichloroethylene, but no less accusatory.
* Cecil Adams of The Straight Dope discusses the speed of the flow (note that Adams apparently supports the conspiracy theory that USIA decided to fill up the tank to distill molasses into grain alcohol for liquor before Prohibition killed the market for good):
I consulted with Gareth McKinley, professor of mechanical engineering at MIT, and established that the theoretical maximum rate of flow for a (roughly) 50-foot column of liquid, ignoring density and viscosity, was 38 mph. Surprisingly, molasses's stiffness would have slowed things only a bit--making certain assumptions about Reynolds number and whatnot that I expect some gratitude for not sharing, the flow rate would have been mostly a function of inertia (i.e., mass) rather than viscosity. Bottom line: 35 mph was a pretty good guess.
Information in this article was taken from the following:
John Mason, “Eric Postpischil's Molasses Disaster Pages, Yankee Magazine Article,” Eric Postpischil's Domain, 29 August 2007, accessed 12 June 2009
Edwards Park, “Eric Postpischil's Molasses Disaster Pages, Smithsonian Article,” Eric Postpischil's Domain, 29 August 2007, accessed 12 June 2009
Puleo, Stephen, "Dark Tide: The Great Boston Molasses Flood of 1919". Beacon Press, 2004, preview available at Google Books
and of course