I think you should call their extension office and ask where the materials for the compost comes from.
Here in Dekalb our compost comes from roadside pick ups of chewed up shrubbery, old leaves and grass clippings. Who knows what people put on their grass? I won't use it in my veggie garden, but I do in the non-edible plants areas.

I've used the Cobb County compost for a while, like GGG I used it in my non-edible beds. However this year I put a load on some of my raised beds. Prior to doing this I researched the compost, it's 'Class A', which is safe for food crops according to the EPA's regulations. Specifically, Class A compost has negligable levels of disease organisms left, vs Class B which has very very low levels. Years ago there was also a concern over compost from residential waste having elevated levels of heavy metals, but due to general EPA regs removing these from products that's no longer much of an issue. The real question is do you trust the facility to maintain their standards, so that it really is Class A with no variation. Only someone with intimate knowledge of the facility would be able to answer that. I guess I do trust it :) I regularly drink tap water over bottled and figure it's safe so there's an example of my mentality for you.

As for what's in it - you name it. It's 'Bio Blend', which includes treated sewage sludge (poop!) and garbage, with the non-compostable bits filtered out. I've noticed that different batches have varying levels of 'bits' still in it, such as the odd plastic straw or some such. There is also sometimes a slight manure-like smell, which disappears in a few weeks. Overall, however, I think it's good stuff, a fabulous soil amendment for our clay.

As for other chemicals in it, I'm not as concerned because I personally believe the concentrations would be slight. Our backyard has been churned up and used to have a pool in it, I figure there's as much unknown chemical crud in the soil already as there would be in that compost. More important to me is what fertilizers and chemicals I spray on my plants, which is next to none.

Interestingly, I read articles about the Cobb facility regarding public perception of the compost, and the fact that it has an image problem because of the source of the raw materials. They'd need some marketing campaign to make people feel comfortable with it, as there is a general distrust of anything with human sludge in it. But with proper treatment, it's a safe as potting soil, but no one instinctively trusts it. We'll see how my veggies turn out this year.

Last weekend I attended a presentation on composting at the Southeastern Flower Show. According to the presenter, grass clippings from treated lawns are safe to use in compost for the garden, because the chemicals will burn off during the composting process. She is an organic gardener, and says that she will use grass clippings from her neighbors, etc. in her own garden, so I would think that that shows confidence.

Unfortunately, chemicals do not "burn off" and using grass from chemically treated gardens does not fall into the definition of organic.
I follow both the USDA guidelines for organic growing and the American standards for "All Natural"- grass clippings from treated lawns are not acceptable.