Category Nuances for noxious_gas:

• dangerous,
• irritating,
• undesirable,
• odorous,
• explosive,
• noxious,
• occupational,
• unpleasant,
• impure,
• hazardous,
• lethal,
• toxic,

Simple Categories for noxious_gas:

• situation,
• substance,
• contaminant,
• equipment,
• gas,
• residue,
• material,
• hazard,