If its being used like other essential oils are for pest control, eg creating a boundary/barrier, it might be ok. If the tortoises are in an area that would be saturated with a oil/water mix/spray, or in contact with the concentrated oil then I wouldn't.
Planning on spraying on the walls and under the deck. Planning on picking up my tortoises the day i spray. Its over 100 already so it will probably be vaporizing. Most of spraying will be front yard and garage plus indoors to avoid the tortoises. My male has been stung twice now and had severe ataxia both times. Im concerned another sting could kill him.