A Gas Mask script written for QBCore
Add this to your shared.lua:
['gasmask'] = {['name'] = 'gasmask', ['label'] = 'Gas Mask', ['weight'] = 100, ['type'] = 'item', ['image'] = 'gasmask.png', ['unique'] = false, ['useable'] = true, ['shouldClose'] = true, ['combinable'] = nil, ['description'] = 'Protect you from some nasty gasses'},
Then start the script.
You'll need to add an image for it as I haven't done this.
Credits to FiveMGasMask for the idea/base