We have all seen the commercial fertilizing trucks with the pictures of pets and children on the side. Do not be misled by the images fertilizer can be poisonous to children and pets. There is a reason why when they finished there is a "keep off the grass" sign left behind reminding people that the lawn has been fertilized and to stay off for about an hour.
There are two ways to fertilize your grass, liquid fertilizer that is sprayed on and the chemical of choice for most commercial companies or dry fertilizer which most do-it-yourselfers use. Commercial companies do offer this dry type of fertilizer but you have to ask for it.
Although companies say that after an hour pets and children are safe the time for safety is more like 24 hours. Liquid fertilizer is by far more harmful because you cannot see it on your dog when they roll around the grass, as dogs normally lick their paws and clean him or herself, ingesting the fertilizer will cause harm.
Dry fertilizer, although it can be seen should your dog roll around, it will work its way between toes and can be easily digested when they clean their paws. Once the dry chemical is watered into the lawn your dog is good to go.
The best way to handle the safety of your pets is to keep them off fertilized grass until it has been watered in. If you use a commercial company request dry granular fertilizer instead of the liquid chemical, when you arrive home look for the sign they leave behind. If your lawn was treated plan on taking your dog for a walk to relieve him or herself instead of allowing them on the grass.