and (2) A commercially available non-synthetic (natural) substance is selected in preference to an allowed synthetic substance if the two substances are equally suitable for the intended purpose and there is no discernable difference between the two substances in terms of their effects on soil or water quality.
(A commercially available non-synthetic (natural) substance; is selected; L:in preference to an allowed synthetic substance) (the two substances; are equally; suitable for the intended purpose)
A commercially available non-synthetic (natural) substance the two substances
is selected are equally
L:in preference to an allowed synthetic substance
suitable for the intended purpose