AUGUSTA –– The Senate voted 19-14 Wednesday to back a bill that would establish a blood level limit to determine whether a driver is impaired from marijuana use.

The vote followed a lengthy debate that, much like the national debate over marijuana impairment, did not break along party lines. Supporters argued that setting a blood limit is essential for helping police charge impaired drivers with operating under the influence. Opponents said the proposed limit will ensnare unimpaired drivers because the science is not settled on the appropriate threshold for THC, the psychoactive compound in marijuana.

Some medical marijuana patients have also been critical of the bill, contending that their use of the drug may leave them with residual blood THC levels that would violate the standard.

The debate reflects policy discussions in other states as they grapple with efforts to legalize recreational or medicinal use of marijuana. A majority of the Criminal Justice and Public Safety Committee voted against the bill March 10. The bill, L.D. 1628, now shifts to the Democrat-controlled House of Representatives.

Maine already has a medical marijuana law. A bid to legalize recreational use could appear before voters in November, pending a decision by a Superior Court justice on whether supporters submitted enough valid signatures to qualify for a ballot question.

A number of laboratory studies have determined that marijuana degrades one’s driving ability. However, research on whether it plays a role in accidents has been mixed.


According to the National Conference of State Legislatures, 17 states have laws setting limits on THC in the bloodstream while operating a vehicle. Several of those states have set the amount between 1 and 5 nanograms per milliliter. The Maine bill seeks to impose a 5 nanogram limit – the same as in Colorado and Washington, where recreational marijuana use is legal.

Some supporters of the bill agreed to strip the 5-nanogram threshold in order to establish testing protocols, but that effort fell short.

Police already test for alcohol after fatal crashes and request testing for the presence of drugs.

Steve Mistler can be contacted at 620-7016 or at:

Twitter: @stevemistler

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