Green or Unclean: Bare Escentuals Active Cell Renewal Night Serum

Bare Escentuals has a new serum. They've been giving free samples of this with purchases and for stopping by their boutiques. I got a sample myself recently.

This has a Skin Deep Rating of 4

This serum promises to work while you sleep to help create firm, healthy, and younger-looking skin.

This is formulated without:
- parabens
- sulfates
- synthetic fragrances
- synthetic dyes
- petrochemicals
- phthalates

Ingredients: Water/Aqua/Eau, Butylene Glycol, Propanediol, Glycerin, Xylitol, Saccharomyces/Xylinum/Black Tea Ferment, Glycyl Glycine, Methyl Gluceth-10, 3-O-Ethyl Ascorbic Acid, Soil Minerals, Soil Minerals/Syringa Vulgaris (Lilac) Leaf Cell Culture Extract, Palmitoyl Tripeptide-5, Zizyphus Jujuba Seed , Phytoecdysteroids Extract, Maltodextrin, Ppg-13-Decyltetradeceth-24, Ethylhexylglycerin, Ammonium Acryloyldimethyltaurate/Vp Copolymer, Peg/Ppg-14/7 Dimethyl Ether, Potassium Sorbate, Sodium Benzoate, Trisodium Edta, Lavandula Hybrida Oil, Limonene, Citric Acid, Citrus Aurantium Dulcis (Orange) Fruit Extract, Tocopherol, Citronellol, Geraniol, Phenoxyethanol, Xanthan Gum

In general, I'm okay with using products with a Skin Deep Rating under five (I am transitioning to using all natural products). However, I saw that the ingredient was Butylene Glycol, which reminded me of Propylene Glycol, an ingredient I avoid. It turns out that Butylene Glycol is a humectant. However, sources vary on whether or not it's a good  ingredient. The FDA has approved it for use in cosmetics and as a food additive. Yet others list this as a skin, lung, and eye irritant. The books on green beauty I have also differ about whether or not this is an ingredient to avoid. O.o I suppose it's better safe than sorry, so I'll put this aside in favor of a more natural serum.

Can anyone shed some light on Butylene Glycol?

~ Susan