The CPSC has decided that this is A-OK and poses no risk to children, which as far as I'm concerned, is just further evidence that CPSC has sold itself so many times it long ago lost track.
It gets better: "cadmium, zinc and benzene" in the tire crumbs used to cushion the field.
Further investigations from other agencies to follow later in the year. Sensibly, at least some of these will look at a wide range of possibly dangerous chemicals, and look into the possibility that someone might not only inhale stuff out-gassing in the sun, but also face plant and therefore ingest, or fall and abrade and get some in through a cut in the skin. There are also water runoff concerns.
Very NY-centric coverage here: