MADISON, Wis. (AP) -- A state lab is facing a backlog of nearly 1,000 blood samples from suspected intoxicated drivers.

The Wisconsin State Laboratory of Hygiene is now taking five to seven months to determine if drivers had drugs such as cocaine or Valium in their system. It's due to stagnant staffing levels and a caseload that has increased nearly 90 percent since a 2003 change in state law.

That law says drivers are guilty of driving while intoxicated if they have any detectable amount of illegal drugs such as methamphetamine or marijuana in their system. Prosecutors previously had to prove the defendant's driving was actually impaired by the drugs.

Dane County District Attorney Brian Blanchard tells the Wisconsin State Journal that the backlog wastes time for courts, prosecutors and public defenders and puts the public at risk.