The laws and legal decisions around the use of drug dogs are something of a patchwork, leaving states grappling with what to do.

Some departments in states that have legalized marijuana have decided to keep their current dogs and take their chances in court, said David Ferland, the executive director of the United States Police Canine Association, a training and certification organization. Others have shifted their dogs’ duties, using them only in places where marijuana remains off limits, like jails and schools.

Many departments are trying to future-proof themselves by dropping marijuana from their training programs. “Almost every state is trying to get ahead of this,” Mr. Ferland said. “Nearly every one is having some newly trained teams not introduce marijuana odors to their dogs.”

But some are holding out. In Kansas, which shares a border with Colorado, cannabis is still part of the curriculum for canine trainees.

“The issue is on our radar, and we watch and research what states are doing as legalization crawls across the United States, but as of today all of our dogs are still imprinted on marijuana odor,” said Chad McCluskey, the master trainer for the Kansas Police Dog Association. “We are not considering a change to that approach.”

Michigan, which this month became the 10th state to legalize marijuana for recreational use, is trying to figure out what to do with the 50 dogs used by its state police.

“We’re still reviewing the law’s impact on our operations and determining next steps,” said Lori Dougovito, a state police spokeswoman.