[Shawna]

No, I don’t think limonene has been pulled. Merck Vet Manual discusses it.

“d-Limonene

d-Limonene is used for flea control on cats and for other insect pests. At recommended dosages, the solution containing d-limonene appears to be safe. Increasing the concentration 5 to 10 times in sprays or dips increases the severity of toxic signs. These signs can include drooling, tremors, lack of coordination, and dangerously low body temperature. In dogs, ingestion of d‑limonene by mouth causes vomiting.” http://www.merckvetmanual.com/pethealth/special_subjects/poisoning/insecticide_poisoning.html

I wholeheartedly agree that just because something is natural doesn’t make it inherently safe. That was not the argument here though, it was whether natural is “effective” or not. When evaluating safety you have to look at quality of product too.