The ASPCA sent me a couple reference articles on cats and essential oils safety.
Lastly, I spoke with Young Living's Product Support about the subject of cats and essential oils. They stated that:
Please refer to my article on Essential Oils Toxicity for Cats for additional information.
an eclectic witch, certified aromatherapist, herbalist, perfumer, skincare formulator, and incense crafter who specializes in unique creating handcrafted perfumes, bath products, skincare products, soaps, shampoo bars, aromatherapy products, incense blends, ritual oils, botanical charms, candles, and ritual and spell supplies.