I own a marijuana dispensary. Will I get in trouble if a customer does something stupid after visiting my shop?

I DON'T THINK SO, but anything is possible.

You may have been alarmed by the recent Colorado lawsuit where a man named Richard Kirk shot and killed his wife after consuming a cannabis edible. This happened in 2014, but the Kirks' kids and other family members recently sued two Denver-based marijuana companies: the processor that made the product, and the dispensary that sold it. As for Kirk, he was charged with first-degree murder and pled guilty, but switched his plea to not guilty by reason of insanity. Kirk claims that cannabis rendered him insane at the time of the slaying.

There is a lot to cover here, and the trial court has many facts and opinions to parse. We know that the edible in question contained 10 servings of THC, with each serving containing 10 milligrams. We also know that a toxicology report showed that Kirk had just 2.3 nanograms of THC per milliliter of blood the night of the shooting. That ratio is well under the 5.0 nanogram legal limit for stoned driving in Colorado. (We don't have a limit yet in Oregon.) And there is backstory about how Kirk and his wife, Kristine, had been fighting and how Mr. Kirk was not doing so hot overall.

Still, Kirk's attorneys argue that the THC in his system may have triggered a psychotic break. And he did seem to be acting crazily—the night of the murder, Kirk ranted about the world's end and jumped in and out of windows. On those facts, the survivors are chasing the vendors for "failure to warn that edibles could lead to paranoia, psychosis, and hallucinations." They also allege that defendants "negligently, recklessly, and purposefully concealed vital dosage and labeling information... to make a profit." That sounds quite sinister, but may be hard to prove.

This type of litigation is not my bailiwick, but I can tell you that wrongful death suits are tough. To prevail, plaintiffs would need to show that the defendants' actions made it foreseeable that Kirk would murder someone; second, that the THC Kirk ingested was the cause ("actual or proximate") of this tragedy. Generally speaking, causation is a bear in many injury and wrongful death actions: The Portland woman who just sued Bullseye Glass for her lung cancer affliction will face the same challenge. In the pot lawsuit, I will be very surprised if plaintiffs clear the bar.

As a dispensary, you can insulate yourself from these types of filings by following all state packaging and labeling requirements to a T, working with reliable suppliers, and training your staff to be discerning salespeople. You can also take solace in the fact that we don't hold bottle shops liable for drunk driving wrecks, and you can hope for similar, sensible outcomes in weed.