The GasMask addon adds another layer of complexity to deep-cave exploration in Minecraft by making the environment poisonous. There won't be enough oxygen to breathe below a depth of 44, and you will start losing HP rapidly. To deal with this, you will need to use a gas mask and disposable filters. This creates the risk of going too deep into the caves and introduces a cool new challenge to overcome.
Credits: SystemTv
[attachment=3917:Download GasMask BP 1.21.2] [attachment=3916:Download GasMask RP]