2,2,5-trimethyl-3-dichloroacetyl-1,3-oxazolidine is exempted from the requirement of a tolerance when used as an inert ingredient in formulations of the herbicides S-ethyl dipropylthiocarbamate, S-propyl dipropylthiocarbamate, and S-ethyl diisobutylthiocarbamate applied to corn fields before the corn plants emerge from the soil with a maximum of 0.5 pound of the inert ingredient per acre.