  The statistics of the energy and helicity fluxes in isotropic turbulence are
studied using high resolution direct numerical simulation. The scaling
exponents of the energy flux agree with those of the transverse velocity
structure functions through refined similarity hypothesis, consistent with
Kraichnan's prediction \cite{Kr74}. The helicity flux is even more intermittent
than the energy flux and its scaling exponents are closer to those of the
passive scalar. Using Waleffe's helical decomposition, we demonstrate that the
existence of positive mean helicity flux inhibits the energy transfer in the
negative helical modes, a non-passive effect.
