Modern buildings are increasingly fitted with energy efficient windows that are filled with argon (Ar), a colorless, odorless, and non-toxic gas. Alongside the more expensive krypton gas, it’s the most commonly used gas fill for windows.
During the manufacturing process, argon is pumped between the window panes. As the gas enters the space between glass, it pushes out oxygen because argon is heavier than oxygen. The process is monitored by oxygen analyzers.
Another likely application is monitoring oxygen in the production area for energy efficient windows to protect employees from the dangers of an oxygen deficient atmosphere.
If argon leaks during the manufacturing process and is released into atmosphere it will displace oxygen, the air in the room will become oxygen-deficient. Since argon is colorless and odorless, workers in an area that is not monitored with an oxygen monitoring instrument will be unable to detect a leak, and thus unable to escape before suffering respiratory problems.