(ABC 6 News) — An Iowa-based convenience store, Casey’s, is facing a lawsuit after being accused of exploiting its workers.

The suit centers around a $35 per paycheck surcharge added to tobacco users’ health insurance bills. It claims Casey’s is illegally shifting the costs associated with less healthy workers from the company back to workers.

Further, the suit claims the store has failed to provide federally required options, allowing workers to avoid that surcharge.

Casey’s has denied any wrongdoing.