The Senghenydd Colliery Disaster, also known as the Senghenydd Explosion (Welsh: Tanchwa Senghennydd), occurred in Senghenydd, near Caerphilly, Glamorgan, Wales, on 14 October 1913, killing 439 miners and one rescuer. It is the worst mining accident in the United Kingdom, and one of the most serious globally in terms of loss of life.