The former New York Yankees outfielder's 14-year-old son died on March 21 during a family vacation in Costa Rica.

A toxicology report after his death found high levels of carboxyhemoglobin, an indicator of carbon monoxide in the blood, according to a statement from Randall Zúñiga, the director of the Costa Rica Judicial Investigation Agency. Miller Gardner’s test showed a saturation of 64 percent, he said, adding that anything over 50 percent was lethal.

Officials in Costa Rica confirmed Wednesday that the official cause of death for 14-year-old Miller Gardner was carbon monoxide poisoning.

Miller Gardner, the youngest son of former New York Yankees outfielder Brett Gardner, died at the age of 14 while on vacation with his family.

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.

The death of Miller Gardner, the 14-year-old son of former New York Yankees outfielder Brett Gardner, at a beach resort in Costa Rica is believed to be related to carbon monoxide inhalation, the Judicial Investigation Agency (OIJ) of the Central American country said Monday.

A new toxicology report found the 14-year-old South Carolina boy's body had carboxyhemoglobin level of 64%, which is 14% above what is considered lethal.