Suppression of Hadroproduction in Nuclei

We argue that nuclei are not transparent for fast projectile partons. Color transparency is effective for final state interactions in heavy particle production, though nuclear filtering of initial partons can reduce the cross sections. We show that short-ranged initial state interactions, which have been neglected so far, can be important in hadroproduction on nuclei. With the present scenario of hadroproduction a qualitative description of data can be obtained.