[brucepick]

Re. safety -
I found this on the Wikipedia page on "silica gel":

Silica gel is non-toxic, non-flammable, and non-reactive and stable with ordinary usage. It will react with hydrogen fluoride, fluorine, oxygen difluoride, chlorine trifluoride, strong acids, strong bases, and oxidizers.[6] Silica gel is irritating to the respiratory tract and may cause irritation of the digestive tract, and dust from the beads may cause irritation to the skin and eyes, so precautions should be taken.[8] Some of the beads may be doped with a moisture indicator, such as cobalt(II) chloride, which is toxic and may be carcinogenic. Cobalt (II) chloride is deep blue when dry (anhydrous) and pink when moist (hydrated).

Crystalline silica dust can cause silicosis but synthetic amorphous silica gel is non-friable, and so does not cause silicosis.

Re. where to get it:

I found multiple versions when I searched for "Silica gel" on Amazon. Below are a few offerings that might be worthwhile for individuals - not necessarily for a group buy:

Amazon.com: 4 pack of 112 Gram Silica Gel Desiccant Packets 6" x 4.5" By Dry-Packs Brand! Prevent Mold, Mildew, Odors, and Corrosion!: Office Products

Amazon.com: Peli Desiccant Silica Gel, 4-Pack: Home Improvement

Amazon.com: Dry-Packs Portable Dehumidifier Box - 450 Gram Silica Gel - Protects 33 CU FT! Can Be Reactivated, Indicator Included!: Home Improvement