Theo,
I thought the same thing about the treatment. After followup with my neighbor and another friend in the road construction business, they both confirmed due to EPA laws etc...any material used near any water way according to TX laws has to be eviromentaly friendly. That includes potenial run off and aquifers as well. Both assured me that these meet state spec. Living 45 miles from Austin in the most PETA friendly area, short of San Fransico, these are good.
