The coal industry continued despite several disasters, including an explosion at Wilkes-Barre's Baltimore Colliery in 1919, which killed 92 miners. The industry declined when the United States switched to other energy sources, and most coal operations had left Wilkes-Barre by the end of World War II. The 1959 Knox Mine Disaster, resulting in the flooding of numerous mines, marked the end of large-scale coal mining in the area. Industrial restructuring also caused the city to lose jobs and begin a decades-long decline.