  Limits on the regions of $Q^2$ and x where the operator product expansion
canbe safely used, at small values of x are given. For a fixed large $Q^2$
there is an $x_0(Q^2)$ such that for Bjorken x-values below $x_0$ the operator
product expansion breaks down with significant nonperturbative corrections
occurring in the leading twist coefficient and anomlous dimension functions due
to diffusion of gluons to small values of transverse momentum.
