Dark Tide: The Great Boston Molasses Flood of 1919, by Stephen Puleo, is a fascinating account of, well, you can tell from the subtitle, can’t you? It could have used another pass by an editor, but is otherwise an enjoyable and interesting read.
This was no small accident, resulting in the longest trial and the largest industrial accident damage award at the time. Why was a multi-million gallon molasses tank erected in a crowded section of Boston? Why was it done so in haste? Why wasn’t its design studied by an engineer for safety? Why was it never tested for structural integrity? Why did some believe the collapse was an act of terrorism by anarchists? (The trial proved otherwise.) Read and find out.
As for how molasses kill:
Unlike an ocean wave, whose momentum is concentrated in one direction, the wall of molasses pushed in all directions after it escaped the confines of the tank, so that it was more like four separate walls of viscous liquid smashing across the wharf and into the street. Add to that the speed which which the molasses traveled — thirty-five miles per hour initially — the fact that the tank itself disintegrated into deadly steel missiles, and that thousands of fastening rivets turned into lethal steel bullets, and the result was destruction in a congested area equal to that of even the worst natural disaster. […]
“Molasses, waist deep, covered the street and swirled and bubbled about the wreckage,” a Boston Post reporter wrote. “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.