Lawmakers there approved the proposal on a voice vote Tuesday after debating whether a THC level of 5 nanograms was appropriate. THC is the psychoactive ingredient in marijuana.

Ohio and Nevada have a 2 nanogram limit and 12 states have zero tolerance laws for driving under the influence of an illegal drug.

Democratic Rep. Claire Levy proposed setting a limit of 8 nanograms to ease concerns from medical marijuana advocates who say daily users of the drug develop a tolerance that may allow them to drive safely and would be unfairly punished with a 5 nanogram limit. Levy's amendment was rejected.

The bill faces a final vote in the House before it can advance to the Senate.

(Copyright 2011 by The Associated Press. All Rights Reserved.)