Miller Gardner, son of former New York Yankees outfielder Brett Gardner, died from carbon monoxide poisoning, according to Costa Rica officials.

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.

Brett Gardner’s son died of carbon monoxide poisoning. Carbon monoxide is known as the “invisible killer” because it is a colorless, odorless, tasteless gas or liquid. Here’s how to protect yourself and your family from carbon monoxide poisoning while traveling.