  We present a Monte-Carlo program for the simulation of polarized deep
inelastic scattering at next-to-leading order in QCD matched to parton shower
programs building on an existing implementation of the unpolarized case in the
POWHEG BOX package. We discuss extensions of the POWHEG BOX framework necessary
to account for polarized initial states and validate the code by detailed
comparisons to existing fixed-order results. We then use the new tool to make
predictions for the upcoming Electron Ion Collider. We find that parton-shower
effects do have an impact on experimentally accessible distributions and
improve the agreement with the next-to-next-to-leading order results.
