"Please be wary of any animal practitioner or supplier of essential oils claiming that their products or techniques are completely safe to use with cats: the statement is both inaccurate and unsafe. No matter what their claims say, nothing will change the unique physiology of a cat".
IMO it is absolutely negligent from a company to claim that their product containing EO is safe, without even knowing how much or how often the consumer applies the product on their cat. Just because some EO's might take longer for the cat to show a toxic effect, doesn't make them safe. I shudder to think how many cats may have died from "unknown causes" because their owner wanted to avoid harmful pesticides and go natural-using those "safe" claimed products.