The reason is that the lungs have a large surface area with one single cellular membrane that separates the drug from the blood stream. "Like crack, cocaine and nicotine, it's a very efficient and rapid way to get in the body," said Doering.
When cannabis is eaten, the absorption rate is slow and the duration is longer.
"The person is not apt to get what they are looking for -- the familiar high they get in smoking," he said. "Only 4 to 20 percent of the THC even makes it to the bloodstream at all. A good portion is destroyed in the stomach or the first pass through the liver."
"Where the problem comes in when a person expects to get that familiar buzz, decides it's not working, and eat another brownie," said Doering.
"I truly think that edible dosage forms are going to be immensely unpopular with the recreation user whose primary goal is to get high and to get high now," he said. "Of course, if one is good, two must be better. And if two is not enough, then four would be that much better."
Doering concedes that "few people have died of overdoses" on THC. But anxiety attacks are common.
"You feel like you are going to die," he said. "The body releases adrenaline, there can be nausea, vomiting and profuse sweating – all the things that go along with someone who might smoke an extra potent marijuana or hashish."
Meanwhile, Colorado has continued to consult with experts in food safety and regulation. Edible products manufacturers, public health officials, state regulators and laboratory owners were part of a series of meetings last fall and some new rules are being phased in this year.
"We just need to continue to refine the rules as we go," said Department of Revenue spokeswoman Serna. "It's a new industry and we are always looking for feedback from law enforcement and experts in the field. We are really working together and trying to make sure we do a really good job and everyone has a seat at the table."