In chapter 3, as Grace begins his studies of the astrophage, he expresses concern about exposing the samples to normal air. Stratt informs him that the entire room (as well as the sample container) is filled with argon, which appears to have no effect on the astrophage.

Argon is a chemically inert gas and does not react with other substances under typical conditions due to its stable outer electron shell. This makes it ideal for providing a barrier against exposure to oxygen and other highly reactive substances. Useful applications of argon include winemaking and document preservation.

Although argon is the third most abundant gas in Earth's atmosphere (comprising 0.934%), breathing a high concentration of argon can rapidly lead to a phenomenon known as inert gas asphyxiation. While argon itself does not react with the human body, its ability to displace oxygen leads to low levels of oxygen in the bloodstream. However, astrophage don't seem overly concerned about this.