Pets and lawn chemicals

I am trying to locate REAL information regarding which lawn chemicals are hazardous, which are safe.

I find there are so many opinions online, that I can't determine what information has actual scientific backing, as opposed to "it's not organic, so of course it is dangerous" kinds of opinions

I would eventually like to write an article about what is known for certain, what is uncertain, and what is simply unknown as a guide for others.

Any information you might have would be very helpful. I have already found one article in a vet journal that indicates there may be an increase in bladder cancer in dogs exposed to 2,4,D. This is the kind of information I would really like to search out.

Thanks

PS