Carbon monoxide poisoning was cause of Miller Gardner’s death, toxicology report confirms

(CNN) — The death of Miller Gardner, the 14-year-old son of former New York Yankees outfielder Brett Gardner, was due to carbon monoxide inhalation, the Judicial Investigation Agency (OIJ) of Costa Rica said Wednesday.

Gardner was found dead by a family member in his hotel room on March 21, while the family was staying at the Arenas Del Mar resort in Costa Rica.

OIJ director Randall Zúñiga confirmed that the toxicology results and the carboxyhemoglobin test showed a saturation level of 64%. Zúñiga stated that concentrations above 50% of carboxyhemoglobin are lethal.

According to the National Institutes of Health, carboxyhemoglobin is “the complex formed within red blood cells when hemoglobin is exposed to carbon monoxide.”

“In this particular case, it was a strictly scientific effort that allowed us to find the real truth of the facts,” Zúñiga said.

“In the autopsy, in fact, when it was performed, the young man’s organs had a very specific layer, which is generated when a person dies from inhalation of carbon monoxide gases, and that … was visible at the time the autopsy of the minor was performed.”

The official added that tests were also conducted to detect the presence of drugs such as fentanyl, and the results were negative.

On Monday, Zúñiga had said that a machine room next to the hotel room where Gardner was sleeping was “believed to have some type of contamination that could have caused this situation.”

On Tuesday, the Arenas Del Mar resort offered its condolences but said the cause of death was still uncertain at the time. CNN has reached back out to the resort for comment.

‘A beloved son and brother’

Preliminary reports had initially suggested the cause of the teenager’s death could have been “asphyxiation due to intoxication related to food poisoning,” but that was later ruled out.

Other members of the family had felt unwell the night before his death.

Announcing the death of their son last month, Brett Gardner and his wife Jessica said Miller “left us far too soon after falling ill along with several other family members while on vacation.”

“Miller was a beloved son and brother and we cannot yet comprehend our life without his infectious smile.

“He loved football, baseball, golf, hunting, fishing, his family and his friends. He lived life to the fullest every single day.”

Brett Gardner played in Major League Baseball for 14 seasons, all with the Yankees where he was a part of the team that won the World Series in 2009. He retired following the 2021 season.

The-CNN-Wire
™ & © 2025 Cable News Network, Inc., a Warner Bros. Discovery Company. All rights reserved.