CHICAGO (WBBM) – State officials say they have collected millions of dollars in unpaid taxes from gas station operators since they began an aggressive enforcement effort.

LISTEN: Newsradio 780’s Bob Conway Reports

READ MORE: Coronavirus In Illinois: 2,666 New Cases, 10 Additional Deaths

Last year, the Department of Revenue and the Attorney General’s office began a voluntary compliance program, increased audits and intensified collection of unpaid taxes from gasoline station owners, generating about $12.5 million over a 10-month period.

READ MORE: 2 Children, 2 Adults Hospitalized After Crash On Lake Shore Drive

Recently, the effort was stepped up with the filing of criminal charges against five gas station operators. Since then, an additional $9.3 million has been collected for a total of approximately $22 million.

MORE NEWS: Woman In Critical Condition After Being Shot In Car In Park Manor

Gasoline sales are reported on a monthly basis. Officials determined that a fraudulent practice had developed of evading the payment of the taxes by falsely reporting gasoline sales figures.