So I just went to the store and got a few different tubes of silicone. Both the GE Silicone I window & door + Kitchen & bath say that they release acetic acid while curing, while GE Silicone II says it releases methanol and ammonia while curing. All of them say it is not for use below the water line or in aquariums (legal disclosures, I'm sure. DOH!). They all mention some kind of mold free protection:
Silicone I: For a long-lasting seal, choose 100% silicone, not acrylic caulk, which can shrink and crack, leaving gaps for water to seep through. Those leaks can lead to water damage and mold growth.
Silicone II:100% silicone is a 3 hr. Rain-Ready and Sun/Freeze Proof caulk for windows and doors, as well as attics and basements, that also provides mold-free product protection.
Silicone II also mentions that it isn't for use below the water line, aquariums, AND where FDS compliance is necessary