It's rare, but possible, to kill animals with lawn chemicals. In reality, if you dilute and apply chemicals correctly, you won't cause a problem. Walking through a yard, the animal won't pick up much because of the footpads. Birds are more frequently poisoned because they mistake chemical granules for seeds. Eating a grub killed by an insecticide won't cause a problem.
Owners often expose their animals to chemicals with flea collars, flea dips and injections.
But a lawn care chemical could push the animal over the limit. Cats are more susceptible than dogs to chemicals because of their grooming habits and because the enzymes in the body don't handle insecticides as well as dogs. Problems rarely occur from a normal lawn treatment. The only real problems happen with an incorrect dilution which causes run-off into puddles that the animal drinks from. Keep pets out of the yard until the application is dry.