Hard Hat Riot occurred on May 8 , 1970 , in New York City . It started around noon when about 200 construction workers were mobilized by the New York State AFL-CIO to attack some 1,000 college and high school students and others who were protesting the May 4 Kent State shootings , the Vietnam War , and the April 30 announcement by President Richard Nixon of the U.S. invasion of Cambodia . The Hard Hat Riot , breaking out first near the intersection of Wall Street and Broad Street in Lower Manhattan , soon spilled into New York City Hall , and lasted approximately two hours . More than 70 people , including four policemen , were injured on what became known as " Bloody Friday " . Six people were arrested
Kent State shootings
Kent State shootings
Hard Hat Riot