Desethylpropionate Fenoxaprop P is an impurity of Fenoxaprop P-Ethyl, an aryloxyphenoxypropionate compound widely used as an herbicide for control of postemergence annual grasses in crop fields (mostly in rice paddys). Fenoxaprop P-ethyl is routinely used with an agronomic safener in order to minimize the toxic effects of the herbicide on the desired crops.