I see your point. Dig around a bit more and you'll find plenty of studies on rat essential oil inhalation. Because rats are the best legal human model, they are used almost exclusively to get an idea of how humans might respond to different essential oils. I remember one showing that rose oil inhaled in sufficient concentrations sedated rats, to no I'll affect and actually helped hypertensive rats.I'm sure there are benefits internally, but for instance the link you posted was talking about essential oil derived from citrus which is known to cause kidney failure in males, so I wonder if studies are only considering the singular aspect they researched in rats. I do tend to worry too much, so that's very likelybut the respiratory system seems like a potential concern to me. Thanks for your time!
Here's on on lavender. Rats are used almost exclusively to test essential oils since they are the best legal human models. Therefore, a massive amount of scientific data on the subject has been published.