HI XXXXXXX,
Generally lawn fertilizer is not harmful to dogs once it is laid on the lawn. The problem comes from dogs who actually get into a bag of fertililzer and inhale or eat it. You can read about hebicides, insecticides, and fertilizers here.
http://www.petplace.com/dogs/lawn-garden-hazards-in-dogs/page1.aspx
This would have been a dry treatment spread within an hour or two of the dog going on the lawn.
Likely if he got into any of it, it would have been a very small piece of two, but he's a 8 lb Pom. Thats mainly why I am worried - his size?
You though believe the amount, if as small as I believe it is should not be something to worry about?
I don't think you need to worry about it, once it is spread the toxicity is very low. You would be seeing illness such as vomiting if too much was ingested.
dog training consultant
24 years training & behavior,pet first aide, Therapy dog eval., PA Animal Response Team