Miller Gardner, the 14-year-old son of former Yankees outfielder Brett Gardner, dies last week while on vacation with his family in Costa Rica due to carbon monoxide poisoning, authorities confirmed Wednesday.

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.

Brett Gardner's son Miller's cause of death has been confirmed by local authorities nearly two weeks after his death. Miller was in Costa Rica with family when he died on the morning of Friday, March 21.

Miller Gardner, the 14-year-old son of the retired Yankees player Brett Gardner, died from carbon monoxide poisoning while on vacation in Costa Rica. Here’s why the gas is so dangerous.

Costa Rica authorities confirmed that carbon monoxide poisoning was the cause of death of Miller Gardner, the 14-year-old son of former New York Yankees outfielder Brett Gardner.

Carbon monoxide poisoning is reportedly what caused the death of Miller Gardner, the teenage son of retired New York Yankees outfielder Brett Gardner.

Carbon monoxide poisoning was the cause of death of the teenage son of former New York Yankees outfielder Brett Gardner, authorities in Costa Rica confirmed Wednesday night.

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.

A blood test for carbon monoxide showed a saturation level of 64% in Gardner’s body, Costa Rican officials said. Concentrations above 50% are considered lethal.