Appeals court ruling involving six cases might impact thousands of past cases.

TULSA, Okla. (AP) — An Oklahoma appeals court has ruled in six cases that documents used by the Department of Public Safety to revoke driver's licenses following DUI breath tests did not comply with state law, raising questions about thousands of past cases.

The Tulsa World reports ( ) that the state Court of Civil Appeals rulings state that the Department of Public Safety was told of the problem in a 1990 case.

State law requires blood-alcohol test reports to include "a sworn report from a law enforcement officer that the officer had reasonable grounds to believe the arrested person" drove or could have driven a car under the influence of alcohol.

DPS officials say the document in question — the affidavit signed by the arresting officer — has been in use for eight years.