Lawmakers in the Washington House and Senate quietly passed a bill over the weekend that will re-criminalize some marijuana possession, reacting to warnings from the state's crime lab that the current law could make it impossible to prosecute large-quantity possession charges or large-scale marijuana growing operations.

The Senate passed the measure unanimously on Saturday, according to The Associated Press. The governor was expected to sign the bill as soon as Monday, but had not yet by early afternoon. Scientists at the Washington State Patrol's Forensic Laboratory Services warned recently that last November's election changed the definition of marijuana to such an extent that nearly all plants seized by police could be considered hemp.

The trouble arises where the law draws the line between hemp, an industrial fiber that contains virtually no psychoactive drug, and its more intoxicating cousin marijuana. The state's law currently says that if tests show more than 0.3 percent of marijuana's "delta-9 THC," then its a drug, but anything less is considered hemp and therefore not a drug.

Crime lab experts warned that the language does not account for changes that happen to marijuana when it is burned or cooked, causing a plant that might have a low amount of psychoactive drug in it to become very potent once ingested. In other words, officials suddenly realized that their classification of hemp is too broad and technically covers certain varieties of marijuana, opening a window for the drug to be grown and sold as hemp in massive quantities with complete legal immunity, even though it would retain a strong psychoactive effect.

Marijuana, unlike hemp, is still heavily restricted in Washington, where adults over 21-years-old are permitted to possess up to one ounce for non-medical purposes. Sales and distribution are still illegal, but "giving" marijuana without profit is allowed. The state is still working on a more formalized regulatory system.

The bill awaiting Gov. Jay Inslee's (D) signature adds all THC acids to the definition of marijuana, further separating it from industrial hemp.