[Code of Federal Regulations] [Title 21, Volume 3] [Revised as of April 1, 2003] From the U.S. Government Printing Office via GPO Access [CITE: 21CFR182.1711] [Page 463] TITLE 21--FOOD AND DRUGS CHAPTER I--FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) PART 182--SUBSTANCES GENERALLY RECOGNIZED AS SAFE--Table of Contents Subpart B--Multiple Purpose GRAS Food Substances Sec. 182.1711 Silica aerogel. (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 an anti-foaming agent in accordance with good manufacturing practice.