After 14-year-old Miller Gardner, the son of former New York Yankees star Brett Gardner, was ruled to have died by carbon monoxide poisoning, an expert explained how it could have happened.
“If exposure to carbon monoxide is not reversed, the person can die in less than 10 minutes due to brain hemorrhages, irreversible damage to these cells, and to other cells highly sensitive to oxygen deprivation, like those in the heart,” Dr. Maikel Vargas-Sanabria, professor at the University of Costa Rica, exclusively told Us Weekly on Wednesday, April 2. “This ultimately leads to a shutdown of vital functions and cardiorespiratory arrest.”
Vargas-Sanabria, who is not associated with the case, explained that carbon monoxide goes directly into the bloodstream after entering an individual’s lungs, blocking the transportation of oxygen.
“As a result, the oxygen that enters the lungs cannot reach the cells because it can’t be transported through the blood,” the forensic pathologist said. “This leads to chemical asphyxiation, and within minutes — sometimes less than a minute — people begin to feel drowsy, start falling asleep, and after a few more minutes, as brain cells begin to die, they start convulsing.”
The Costa Rican Judicial Investigative Agency (OIJ) confirmed Miller’s cause of death on Wednesday in a statement to Us Weekly.

“In the carboxyhemoglobin test, a saturation level of 64 percent was found,” OIJ’s General Director Randall Zúñiga said. “In such cases, when concentrations exceed 50 percent carboxyhemoglobin, it is considered lethal. In this particular case, with a saturation of 64 percent, the level is clearly well above that lethal threshold.”
He continued, “Therefore, this confirms the police hypothesis that the death was caused by exposure to poisonous gases, specifically carbon monoxide. With this, the case is practically closed. The only step remaining is for the toxicology report from the OIJ Forensic Sciences Department to be forwarded to the Legal Medicine Department, so the expert can include it in the autopsy report.”
During Miller’s autopsy, Zúñiga reported “a very specific layer” was found on Miller’s organs that forms when “a person dies from carbon monoxide poisoning or gas inhalation.”
After the OIJ reported on Monday, March 31, that “high levels” of carbon monoxide were found in Miller’s hotel room at the Arenas Del Mar Beachfront & Rainforest Resort, the hotel pushed back on the agency’s report.
“We understand the concern has grown and to clarify the high levels of carbon monoxide were in a mechanical room that guests do not occupy,” Dana Cohen, spokesperson for the Arenas Del Mar Beachfront & Rainforest Resort, said in a statement to Us Weekly on Tuesday, April 1. “The levels in the hotel room were non-existent and non-lethal. There was an error in this initial reporting. As mentioned, we await for conclusive results to confirm the cause of this unfortunate death.”
Us Weekly has reached out to the resort for a new comment on the OIJ’s definitive cause of death report.
Miller was found dead in his hotel room on March 21 while vacationing with his family, including his father, his mother, Jessica, and his older brother, Hunter.
With reporting by Alejandra Araya Rojas