Albey's Info:
http://www.albeysreptiles.com/incubate-eggs.htm
The asbestos threat grew out of the Libby, CO vermiculite mine that was heavily contaminated - they mined tons of the nasty stuff for almost 70 years. Asbestos contamination is theoretically only a concern with "popped" vermiculite - not the raw stuff that people use for incubation. When vermiculite is heated to a certain heat it exfoliates and it "pops" into this fuzzy, light-weight material that is great for insulation, packing, etc...unfortunately this method of expansion also asbestos fibers from any contaminated vermiculite into the air. So the expansion factories in places like Libby and the unfortunate people who ended up with the "popped" insulation in their homes are at a major risk for asbestos-related diseases - yucky stuff.
Most vermiculite is supposed to be OK and raw vermiculite like reptile keepers use is supposed to be fine but since it contains unregulated amphiboles like winchite and ferro-edenite, I'd just assume not play with fire...I guess its like keeping your leo on sand? (hehe, bad analogy!
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Anyways, perlite is the best but its also harder to use the first time around. The most common starting problems with incubation are too much moisture/humidity and not enough moisture/humidity. Too much kills the embryo and not enough dries out the suckers. Sounds trite, but once you figure out what works best for you, its all good....I personally think too much fussing with the eggs and reopening the containers is the foremost problem when you're just starting out.
Ok, I will shut-up and stop rambling like a raving loon now