On Saturday 17 July 2021 Piyawee Tharasombat was killed by the high level of carbon dioxide in Tham Luuk. The cave is near Mu Si, Pak Chong district, Nakhon Ratchasima province. Local rescue services used breathing apparatus to recover the body of the 41-year old, which was found only 11 m from the bottom of the 5 m entrance ladder.

The cave is known for its bad air. On a visit in September 2017 Chaiporn Siripornpibul was unable to descend more than 3 m down the entrance shaft, with a cigarette lighter not working at this point due to the high carbon dioxide.

https://www.youtube.com/watch?v=ktxHgq5aV8E