1906, Dec 6th:  Monongah coal mine disaster

In West Virginia’s Marion County, an explosion in a network of mines owned by the Fairmont Coal Company in Monongah kills 361 coal miners. It was the worst mining disaster in American history.

In 1883, the creation of the Norfolk and Western Railway opened a gateway to the untapped coalfields of southwestern West Virginia. New towns sprung up in the region virtually overnight as European immigrants and African Americans from the south poured into southern West Virginia in pursuit of a livelihood from the new industry.

By the late 19th century, West Virginia, now a national leader in the production of coal, fell far behind other major coal-producing states in regulating mining conditions. In addition to poor economic conditions, West Virginia had a higher mine death rate than any other state. Nationwide, a total of 3,242 Americans were killed in mine accidents in 1907. In ensuing decades, the United Mine Workers of America labor union and sympathetic legislators forced safety regulations that brought a steady decline in death rates in West Virginia and elsewhere.

Source: History.com