In 1937, Carl Crow traced the beginnings of American Chinese food to San Francisco's Gold Rush:
The white men had heard the usual sailor yarns about what these pigtailed yellow men ate, and one night a crowd of miners decided they would try this strange fare just to see what it was like. They had been told that Chinese ate rats and they wanted to see whether or not it was true. When they got to the restaurant the regular customers had finished their suppers, and the proprietor was ready to close his doors. But the miners demanded food, so he did the best he could to avoid trouble and get them out of the way as soon as possible. He went out into the kitchen, dumped together all the food his Chinese patrons had left in their bowls, put a dash of Chinese sauce on top and served it to his unwelcome guests. As they didn’t understand Cantonese slang they didn’t know what he meant when he told them that they were eating chop suey, or “beggar hash.” At any rate, they liked it so well that they came back for more and in that chance way the great chop suey industry was established.
Peter Smith casts doubt on the story:
[A]s historian Andrew Coe writes in Chop Suey, is that the Sze Yap-born residents of San Francisco’s Chinatown were eating shap suì as an honest reinterpretation of Cantonese home cooking before white San Franciscans "discovered" the dish. Coe says the story appears to stem from something else: "The tale about the bullying of the Chinese restaurant owner does ring true and the punch line about eating garbage suggests a veiled revenge (analogous to a chef spitting in the soup) for decades of mistreatment. Call it a myth that conveys a larger historical truth."