On January 15, 1919, a fifty-foot tall storage tank in Boston collapsed, sending more than two million gallons of blackstrap molasses through the densely populated neighborhood of the North End. The wave of molasses traveled at thirty-five miles per hour and moved with such violent force that it killed twenty-one people, injured hundreds more, and caused millions of dollars of property damage. The Boston Molasses Disaster made national headlines, with photographs of the crushed elevated train trestles and razed buildings reminiscent of many European cities after the recent World War I bombing campaigns. When the courts would not press criminal charges against U.S. Industrial Alcohol for building a structurally deficient tank, the survivors of the Boston Molasses Disaster organized politically to achieve groundbreaking zoning legislation in Massachusetts, which other states later adopted, to protect countless other residential communities from the dangers of unregulated industry.

The Italian immigrants and Irish-American workers of the North End were skeptical of the molasses tank from the start. It was built in 1914 by a subsidiary of U.S. Industrial Alcohol to store blackstrap molasses for their plant across the river in East Cambridge, where the molasses was distilled into industrial alcohol. The alcohol was then sold to munitions manufacturers that supplied the British, Canadian, and French militaries to fight World War I; when the U.S. entered the war, U.S.I.A. supplied it, too. Company executives chose to put the tank in the North End because the neighborhood was “filled with poor Italian immigrants” and “Irish city workers” who they believed lacked the will and political power to oppose it. Boston Building Department employees with no background in engineering approved the tank—which measured fifty feet high and two hundred feet in diameter—as a “receptacle” rather than a “building,” which allowed it to be constructed more quickly. The massive tank loomed over the North End for nearly five years, leaking molasses so frequently that U.S.I.A. painted the tank dark brown to hide its failings. It finally collapsed on an unseasonably warm day in January 1919.

In the weeks following the Boston Molasses Disaster, cleanup crews worked to excavate the bodies frozen in the hardened molasses while U.S.I.A. officials tried to clean up their public relations disaster. In response to the report by the federal Inspector of Explosives detailing the structural weaknesses of the tank, U.S.I.A. tried to blame the tank’s failure on the immigrant victims. The company insisted that the collapse was actually the result of an attack by Italian anarchists, a source of national paranoia in the years after World War I and entirely without evidence in this case. The anarchist specter would serve as U.S.I.A.’s main defense in the press and in the eventual civil case against the company.

Chief Justice Wilfred Bolster of the Municipal Court investigated the cause of the disaster, but in his inquest report he did not argue that U.S.I.A. or the inept political appointees in the Boston Building Department were really to blame. Despite evidence that U.S.I.A. ignored employee reports of tank leakage, Bolster argued that the Molasses Disaster was a metaphor for the greed and corruption within Bostonians themselves. “A public which, with one eye on the tax rate, provides itself with an administrative equipment 50 percent qualified, has no right to complain that it does not get a 100 percent product,” he wrote in his inquest report. The Grand Jury followed Bolster, failing to file any criminal charges despite the overwhelming evidence of corporate negligence and regulatory incompetence.

But the residents of the North End pushed back against the narrative that they were somehow to blame for the Boston Molasses Disaster. They demanded that U.S.I.A. and other companies start to acknowledge a responsibility for public safety. Young Italian immigrant lawyer Vincent Brogna organized a series of mass meetings to call for the removal of the Consolidated Gas Company’s large gas storage tank, known as a gasometer, in the North End before another disaster happened. With the support of Boston City Councilors and the architect Ralph Adams Cram, Brogna collected thousands of signatures and presented them to the state legislature’s Committee on Public Lighting at a public hearing in March. After two months of organized demonstrations and public pressure, the Consolidated Gas Company agreed to demolish their gasometer in the North End. “All of Boston’s North End colony is rejoicing today,” the Boston Globe reported, noting the successful organizing campaign “since the collapse of the giant molasses tank in Commercial st.” This working-class community of supposedly apathetic immigrants had forced a corporation to take their industrial tanks out of the North End.

The state legislature then acted to protect other communities in Massachusetts from industrial accidents. One week after the Molasses Disaster, State Representative Edward A. Scigliano had introduced a bill requiring storage tanks of any “fluids or gases” to be built at least 1,650 feet away from residences. Scigliano represented the North End of Boston, but several of his colleagues on Beacon Hill were under the influence of Massachusetts manufacturers and stalled the bill for months. When Scigliano tried to compromise on the language of the bill, few other legislators budged until State Representative William J. Francis of Charlestown took the floor. Francis’s elderly father was a blacksmith who had worked in the City Paving Yard and was killed in the Molasses Disaster. Most of the well-to-do politicians in the state legislature had no direct connection to the tragedy, but Francis made a personal plea to his colleagues. By July, the State Senate passed the House bill and sent it to Governor Calvin Coolidge, who signed it into law. Other states soon passed similar laws, in part because coverage of the Boston Molasses Disaster in the national media highlighted how commonplace unregulated industrial tanks had become in early twentieth century American cities.

In 1925, six years after the tank collapsed, the survivors of the Boston Molasses Disaster found some semblance of justice when U.S.I.A. was found liable in a civil suit and had to pay $600,000 (over $8.6 million today) to the relatives of those killed. But the people of Boston more broadly had found their own justice against corporate greed and government incompetence by organizing politically and insisting on the right to basic safety in their homes and workplaces. Their efforts would protect not only the North End, but communities across Massachusetts and eventually across the United States. In the North End of Boston, at least, there is no molasses tank looming over the winding streets now. In its place is a public park on the waterfront, with bocce courts and views of the Bunker Hill Monument.