Miller Gardner -- the 14-year-old son of former New York Yankees outfielder Brett Gardner -- died from carbon monoxide poisoning, Costa Rican authorities have said.

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.

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.

Costa Rican authorities believe Brett Gardner's 14-year-old son Miller died as a result of carbon monoxide poisoning. Randall Zúñiga, director of the Judicial Investigation Agency in Costa Rica, said a toxicology report on Miller found a lethal amount of carboxyhemoglobin saturation,

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.

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

The toxicology results are in, and the carboxyhemoglobin test found a saturation of 64%. Concentrations above 50% are already lethal,” said Randall Zuniga, director of the investigative agency, in a statement.