Early on the morning of May 24, 1932 – just as social unrest reached its peak in Depression-era Monterrey – 240 workers barricaded themselves inside the ASARCO smelter. As news of their sit-down strike spread, hundreds of strike supporters gathered outside the plant's gates. Present were the smeltermen's wives and children, unemployed workers, and residents of the surrounding neighborhood. ASARCO's workers struck as they did – in defiant violation of the labor law – to force management to sign a collective contract with their union. The action culminated a violent season of labor protests and hunger marches in the streets of Monterrey. As an alarmed public would have read in the press, Communists directed both the demonstrations and the ASARCO union. The sit-down strikers held firm as authorities beseeched them to exit the smelter. Late in the afternoon, the president ordered federal troops and mounted police to the scene. Faced with the threat of military intervention, the workers exited from the smelter. As they did, a skirmish broke out between police and union sympathizers. The ensuing melee left one worker dead and dozens of men, women, and children injured. Further protests were silenced by a military occupation of downtown Monterrey. The ASARCO strike ended in tragic defeat. But it symbolized a visible transformation of working-class attitudes and behavior in the industrial regions of Mexico.