(AP) — The Delaware Department of Labor is investigating a construction training program after participants said it exploited them.

The News Journal of Wilmington reports that the Interfaith Community Housing of Delaware's HomeWorks program is a "pre-apprenticeship." The 16-week program aims to teach carpentry basics while allowing participants to earn a certification. It is structured to be part unpaid class time and part paid on-the-job training. The state granted the program $167,000 its pilot year.

Participants say they often ended up working during class time for free, including on some properties the group was renovating to resell. Nine former participants, mostly black men with criminal records, told the Journal the nonprofit used them as free labor.

Interfaith Director Gary Pollio said there is room for improvement but defended the nonprofit's practices.