On July 22, 1972, a fire broke out at the Blacksville Number 1 mine in Monongalia County. It was sparked by a continuous mining machine that came into contact with an electric wire.
The volatile Pittsburgh coal seam at Blacksville ignited quickly. At the time, 43 men were underground; 34 escaped, but nine men who were working deep in the mine died after inhaling smoke and fumes. Days later, the mine was sealed at the surface to protect rescue workers from potential explosions.