The Smoke Tragedy left 355 workers dead in the underground copper mine of El Teniente, Chile.

The 1945 El Teniente mining accident, known locally as the Smoke Tragedy, is the largest mining accident in metal extraction in the history of Chile and, as of 2005, worldwide. It happened on June 19, 1945, in Chile's El Teniente mine in the Andes, which belonged to Braden Copper Company, a subsidiary of Kennecott Copper Corporation, both of the United States. A total of 355 men died, largely because of a nearby fire whose smoke trapped the workers in tunnels and resulted in carbon monoxide poisoning. Another 747 men were injured by the smoke.

El Teniente is the world's largest underground copper mine, located in the Andes Mountains of central Chile at an elevation of 2,300 metres (7,500 ft) above sea level. It is operated by the state-owned mining company Codelco and constitutes the largest division of its operations. Mining at the site dates back to at least 1819, but large-scale industrial extraction began in 1906 under U.S. ownership, initially through the Braden Copper Company and later Kennecott Copper Corporation. In 1971, during the presidency of Salvador Allende, Chile nationalized its copper industry and acquired full ownership of El Teniente. The mine contains more than 3,000 kilometres (1,900 mi) of tunnels and employs about five thousand workers. It was the site of the 1945 Smoke Tragedy, the deadliest metal mining accident in Chilean and world history. Since 2011, El Teniente has been undergoing a major expansion known as the New Mine Level project, which aims to extend operations deeper into the mountain without halting production.

June 19 is the 170th day of the year in the Gregorian calendar; 195 days remain until the end of the year.