I would view Terro as "spot killing" without excess. Unlike a spray (that has overspray), the ant comes to Terro and then brings back a minor residue that kills others in the nest. I think that is an environmentally sensitive method and the method of distribution through the traps mitigates the risk to pets somewhat.
Once, at my parents house, I had to keep a fresh trap in one place for about 4 months before the ants stopped coming....For all I know, I may have killed half the ants in southern indiana.

