A bar of Hershey’s chocolate is a simple pleasure—milky flavor, iconic brown-and-silver wrapper, traditional American roots. But though Hershey’s is among the most beloved and recognized brands in the U.S., the company’s history isn’t as simple as its flavors—like the time when it brutally suppressed a sit-down strike in the 1930s.

Life was relatively sweet in Hershey, Pennsylvania, an idyllic company town designed and built from the ground up by its namesake, Milton S. Hershey. The company’s owner was famous for his rags-to-riches success story and his commitment to philanthropy. Employees made high wages and lived in their own homes on quiet streets that personified small-town life. And long before things like pensions, health insurance and other social services were common, Hershey Chocolate Corporation had them.

When the Great Depression hit, life in Hershey started to seem even better. Other company towns crumbled as their factories went into decline, but when Americans began to buy less chocolate, Milton Hershey paid employees to work on town improvements instead.

But as social historian Robert Weir notes, Hershey himself could be cold, paternalistic and domineering. He felt his workers owed him everything—after all, he had given them everything. But, as with the residents of other company towns, Hershey factory workers became increasingly uncomfortable with the company’s oversight of their private lives and disliked how the entire town revolved around one man—a man who lived in a mansion on a hill, overseeing their lives and fortunes.

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When Hershey reduced working hours and stopped paying bonuses, workers became even angrier. And they felt inspired by the recent sit-down strike at General Motors, which had lasted 44 days and resulted in both union recognition and a pay raise.

Sit-down strikes, in which workers effectively occupied their factories until their demands were met, were the tactic of choice during the Depression years. “They certainly gave workers a psychological boost,” says Weir. Not only did they cripple a factory’s production, but they gave the grievances of striking workers a media platform as reporters rushed to cover the unrest.

All of these factors made a sit-down an attractive choice for Hershey workers in 1937. After unionizing most of the factory under the United Chocolate Workers Union, Hershey workers got a small pay raise. But then Hershey laid off many of the strike organizers. Though it was only weeks old, the union decided to strike.

The strike began on April 2, 1937. Unlike the GM strike, which had been carefully planned for months, this one was no well-oiled machine. For many workers, writes historian Michael D’Antonio, the strike felt “more like a family squabble than an angry revolution,” and each employee’s personal acquaintance with Hershey may have complicated the union negotiations. The widowed Hershey, meanwhile, watched events unfold from his lonely mansion.

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Though spirits were high on the plant floor, the strikers made several tactical errors that would soon spell disaster. They didn’t close the entire shop, and many workers came into work anyway during the strike. They agreed to leave the plant for negotiations, effectively ending the sit-down. And even when they returned to their occupation of the plant, the strikers failed to make plans for the huge quantity of milk that would sit idle during the strike.

The milk—critical to the chocolate that made Hershey’s one of the most famous brands in America—was provided by local farmers. Now, 240,000 quarts of it—enough milk to fill more than 1,600 bathtubs—stood spoiling on the factory floor. In town, opinion began to split between unionists and those loyal to Hershey. Crowds of anti-strike protestors gathered at rallies, many of them farmers whose livelihoods depended on the factory.

After five days of the sit-in, chaos broke out on April 7. Thousands of farmers, joined by loyal employees, stormed the factory and assaulted the strikers with fists, shoes, clubs, improvised weapons and even ice picks. As The New York Times put it, it was a spontaneous action organized by angry farmers who administered “the indignity, not to say the physical pain, of an old-fashioned walloping” before quickly leaving the scene to tend to their fields and cows.

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By some accounts, the reality was quite different. According to oral history interviews housed in the Hershey Corporation archives, some strike participants believe that Hershey itself had orchestrated the riot, bringing in strikebreakers from Pennsylvania and forcing locals, including dairy farmers who relied on their business with Hershey, to participate. “It’s a bit of the Hershey company’s mythology that these were all independent farmers,” says Weir. No matter who was behind the plan, it worked—the violent mob ended the strike.

“Hershey workers abandoned hope of ever bringing a free and unintimidated union to the chocolate town,” writes the plant’s current union. But after legal battles, they finally did unionize as the Hershey Chocolate Workers’ Local and negotiated better wages and benefits.

But the belated victory was bittersweet. The press used the disastrous strike as evidence that sit-down strikes were disruptive and should be banned.

As for Hershey himself, he was privately devastated by the strike. Though he continued to invest in the town he had built—and receive public accolades from his workers—it was clear that Hershey, Pennsylvania, was no model town.

On February 28, 1939, just two years after the Hershey’s strike, the U.S. Supreme Court declared sit-downs illegal.

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