BOGOTA, July 29 (Xinhua) -- Three miners were killed and nine others injured after toxic gas leaked in a gold mine in northwestern Colombia,local authorities said.
"An apparent cause may be the failure in the decompression chamber system. The mine was closed for five days, thus resulted in an accumulation of toxic gas, but the decompression system didn't work," said Cesar Hernandez, director of the Disaster Prevention Department of Antioquia state.
Hernandez said that the gold mine is located in the rural area of "El Bagre", where most of the victims lived.
The injured were taken to nearby medical centers for treatment.
The official also said the mine was legal, and the mining firm is one of the most responsible in terms of safety of mine workers.
Investigators have started to find out the cause of the accident.
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