Not directly. It has mercury gas in it, which can cause problems later in life. It is a heavy metal and once injested, cannot be removed. It can effect your ability to reproduce, and can lead to birth defects.
If you don't breathe oxygen, you die. If you breathe an inert gas like nitrogen (without oxygen) you suffocate. So if you breathe air in a confined space and use up the oxygen you die. If you breathe...
depending on the type of gas. it can be denser than oxygen and stay in your lungs longer, or just in general it sufficates you by not allowingoxygen to enter you lungs. or it could be poisinous