The Iowa Civil Liberties Union is concerned about random drug checks of visitors at the state’s prisons. Officials have started screening people with high-tech machines that scan for residue from drugs and explosives. I-C-L-U spokesman Randall Wilson is concerned some visitors could be falsely accused.Wilson says the I-C-L-U also wants to know how the corrections department plans to use the information.Wilson says if it’s okay for prison officials to use this type of technology on visitors from the outside — the same will soon be true in the workplace.A law allows the checks at the state prisons to try to keep visitors from passing drugs and weapons to an inmate.