Carbon monoxide poisoning killed the 14-year-old son of former New York Yankees star Brett Gardner, a Costa Rican official announced Wednesday. A toxicology report confirmed lethal levels of carboxyhemoglobin ― a compound that forms in exposure cases ― in the blood of Miller Gardner, the official said in a statement reported by CRHoy.com.

Former Yankees player Brett and his wife, Jessica, announced last month that their teenage son, Miller, died on March 21. Here’s what we know about the cause of his death.

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.

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.

Miller Gardner, the 14-year-old son of the longtime Yankees player Brett Gardner, died of carbon monoxide poisoning while on vacation with his family last month, the Costa Rican authorities said on Thursday.

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

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 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.

Miller Gardner—the late 14-year-old son of former New York Yankees outfielder Brett Gardner—died of carbon monoxide poisoning, Costa Rican authorities said Wednesday. The announcement comes 13 days after Miller's death during a family vacation,