avoid any soil with perlite (the little white things). They are "puffed" lava (saimply put) and chams often shoot at light objects in the soil - you do not want him ingesting it. If you cannot find other soil, you can cover it with window screen or, my favorite, Plastic Canvas (see below). It is used in crafts and be found at any store, does not rust, cannot hurt your cham, cheap, and can be cut to any shape or size.
As for other soils, try to avoid soils in general that have fertilizers added. I know this can be difficult to find, but you might have better luck at a nursery rather than garden center.

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0.1 Veiled Chameleon - Luna
1.0 Beardie - Darwin
0.2 felines - Kyndra and Líta
0.1 African Clawed Frog - Skipper
0.3 Mad. Hissers (2 died ;(
0.1 Chilean Rose Hair Tarantula - Rosa Leigh
0.1 Goliath Bird-Eater Tarantula - Natasha
Chameleon Help & Resource Info