The state Comptroller's Office found errors and miscalculations in hauling charges, but no evidence of pervasive intentional overbilling in an audit released Tuesday.
The disaster recovery firm AshBritt received a no-bid contract worth up to $100 million to dispose of debris after last October's mega-storm, while three debris-removal monitors were responsible for calculating transport costs.
Comptroller Matt Boxer was asked to investigate following news reports that towns were being overcharged.
Boxer found vague standards for calculating transport charges, including whether travel within the landfill should be counted.
Municipalities were charged by the mile, with a significant cost jump when transport exceeded 15 miles.