Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

Two poison control doctors from Colorado claim that a patient they treated, an 11-month-old baby boy, died from an overdose of marijuana. The report has ignited controversy — marijuana has not previously been shown to cause a fatal overdose— but some medical experts say the drug might have played a role in the boy’s death.

The child showed up in a Colorado hospital in 2015, barely conscious after having a seizure. The boy was intubated in the emergency room, but his heart began to fail.

“The kid never really got better,” Dr. Christopher Hoyte of Colorado's Rocky Mountain Poison & Drug Center to NBC News' KUSA. “And just one thing led to another and the kid ended up with a heart stopped. And the kid stopped breathing and died.”

Hoyte had been on duty at the poison control center and had been called in to help with the case. After learning that the child’s urine and blood tested positive for marijuana, he and Dr. Thomas Nappe set out to understand whether the drug had actually caused the death. They reported their findings in a journal article in March.

“We just wanted to make sure that we’re not going to call this a marijuana-related fatality if there was something else that we could point at,” Hoyte said. “And we looked and couldn’t find it.”

Related: ER visits for kids rise significantly after pot legalized in Colorado

Their report concluded: “As of this writing, this is the first reported pediatric death associated with cannabis.”

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

Officially, the baby boy died from myocarditis, an inflammation of the heart muscle. In children, the condition is often caused by a virus that reaches the heart muscle, but doctors ruled out viral infection as the cause.

Dr. Noah Kaufman, an emergency specialist who reviewed the report, doubts the findings. “That statement is too much,” Kaufman told KUSA. “Because that is saying confidently that this is the first case. And I still disagree with that.”

Other experts believe that the drug might have played a role in the boy’s death.

“I don’t doubt that a kid that age could get really sick from eating those," said Dr. Andrew Stolbach, a medical toxicologist and emergency room physician at the Johns Hopkins Hospital. "Certainly you see that with synthetic cannabinoids: People develop a fast heart rate and become really agitated, sometimes to the point where the temperature goes up.”

Related: Marijuana users risk schizophrenia

While the heart muscle does indeed have receptors for cannabinoids, that doesn’t mean marijuana would cause myocarditis, said Yasmin Hurd, director of the Addiction Institute at the Icahn School of Medicine at Mount Sinai in New York City.

It’s very likely that the boy had a problem with his heart before ingesting marijuana, Hurd said. “And [the drug] could have been the last straw.”

Edibles and children a 'scary' mix

While Hurd wouldn’t pin the boy’s death on the drug, she does believe that marijuana is becoming a problem for children and young people, especially since the amount of THC — the active ingredient contained in edible products — can vary wildly.

Related: Did marijuana kill this young man? Doctors may never know for sure

Recreational cannabis use was legalized in Colorado in 2014. Since then, the number of emergency room visits by young people has quadrupled, according to University of Colorado researchers. Children are getting access to the drug from parents, grandparents, neighbors, friends, babysitters or other relatives. Most of the time, kids eat food containing marijuana and experience symptoms like drowsiness, dizziness, vomiting, agitation, dangerous heart rates and seizures.

"A lot of the emergency room visits are due to edibles, which can have very, very high concentrations of THC,” Hurd said.

The mix of edibles and kids, “is a really scary scenario,” Stolbach said. “They can look like candy and they’re supposed to taste like candy. So of course a kid is going to be curious.”

Brandon Rittiman of KUSA contributed to this report

Linda Carroll is a regular contributor to NBCNews.com. She is co-author of "The Concussion Crisis: Anatomy of a Silent Epidemic” and “Duel for the Crown: Affirmed, Alydar, and Racing’s Greatest Rivalry."