21 CFR § 582.1711
Silica aerogel
June 25, 2020
(a) Product. Silica aerogel as a finely powdered microcellular silica foam having a minimum silica content of 89.5 percent.
(b) [Reserved]
(c) Limitations, restrictions, or explanation. This substance is generally recognized as safe when used as a component of antifoaming agents in accordance with good manufacturing or feeding practice.