You likely won't see "ethylene oxide" on an ingredient panel. It is a "non-ingredient", a contaminant of some manufacturing processes. 

It has strong links to cancer. 

Look for the following on the label: PPG, PEG, polysorbate and ingredients that end in –eth such as laureth, steareth, ceteareth.

A weak preservative and skin conditioner. While all shampoo should be used with care around the eyes, this ingredient has links to eye toxicity making it very important it does not come into contact with eyes. It is also a known environmental toxin.

Naturally helps increase the flow of blood to the skin with antibacterial, anti-inflammatory, and antiseptic, antiviral and deodorizing properties. 

As with all essential oils, using a high grade essential oil that has been naturally extracted is imperative for the health and safety of your pet!