  We suggest inclusive hadron production in ultra-peripheral proton-nucleus
collisions (UPCs) $p^\uparrow A \to h AX$ as a new channel to investigate
single spin asymmetries (SSAs), in particular, to test the assumed dominance of
the contribution from twist-three fragmentation functions. The UPC cross
sections are obtained by considering the photoproduction limit of
semi-inclusive deep inelastic scattering (SIDIS). In particular, we find simple
formulas for the polarized UPC cross sections in the collinear twist-three
framework. We then numerically calculate the fragmentation contribution to SSA
in $p^\uparrow A \to \pi A X$ at $\sqrt{s} = 200$ GeV and find a few percent
asymmetry in the forward region.
