The University of Illinois Labor Education Program presented the findings of its study called Clean Cars - Dirty Work".
The report found that more than 75 percent of workers in the industry are not getting paid minimum wage. More than 80 percent of them work more than 40 hours a week, according to the study. But only 2 percent of them earned the legal overtime rate.
Study authors say workers from 57 car washes across Chicago participated in the study.