A married couple and their neighbor suffocated to death after discovering a biogas tank leak near their houses, the Vietnamese newspaper Thanh Nien reported Saturday.
At least five other neighbors fell unconscious while attempting to save the couple and later were hospitalized, the media outlet added.
According to the newspaper, one of those who succumbed to the leak remains in critical condition.
In a biogas system, organic waste is turned into methane gas, which many people in rural areas of Vietnam use for cooking and heating. However, a high level of exposure to it can result in suffocation.
