It looked like as soon as they could get close they had a berm of speedy dry along the apron in front of the grass and im sure they removed the soil and clean up after the race. I don't think the EPA would let something like that on national television go. As DW would say "Here come the black helicopters"
I would assume the epa is involved. My understanding is that it involved with the race track since it opened. Way back when. They stocked the infield lake with fish to show how"clean" the track was. For you fisherman, that lake is full of fish. When they remolded the infield. My buddy was working there. He was catch many fish everyday on lunch. He was asked to keep or kill the fish because the were reducing the size of the lake and it would be over populated. BTW there is peacock bass in the lake.