The resort where the son of Yankees outfielder Brett Gardner was found dead denied that the hotel room was contaminated with deadly carbon monoxide — one day after Costa Rican police said that was the teen’s most likely cause of death.

“The levels in the hotel room were non-existent and non-lethal. There was an error in this initial reporting,” the Arenas Del Mar Beachfront & Rainforest Resort told The Post.

The statement refutes a Monday announcement by Costa Rican authorities that there were “high levels of carbon monoxide contamination” in the room where 14-year-old Miller Gardner was found dead.

The FBI is also “closely coordinated” with the investigation, Randall Zúñiga, general director of Costa Rica’s Judicial Investigative Agency announced Monday.

FBI agents had reportedly been at the resort assisting local investigators, a source told US Weekly on Tuesday, however Arenas Del Mar told The Post that no one from the FBI was on-site as of Tuesday afternoon.

The resort did not deny that investigators found carbon monoxide, but claimed the high levels of the deadly gas were detected in a “mechanical room that guests do not occupy.”

Staffers have closed the room “out of an abundance of caution” as they “await for conclusive results to confirm the cause of this unfortunate death,” Arenas Del Mar added.

Authorities initially suggested that Gardner died of asphyxiation related to food poisoning, leading to speculation that he had choked on his own vomit, but they later revealed that he had no blockage in his windpipe.

Investigators then probed the possibility that the teen had an allergic response to medication he may have been given when the family was treated by a doctor after reporting feeling sick to the resort, sources told ABC News.

He was already unresponsive when an emergency medical team was called to the resort Friday, March 21, doctors told The Post.

A nearby pharmacy that makes emergency deliveries to the resort told The Post they delivered no medication on the night before Gardner was found dead, and only made a small delivery of Imodium – which is used to treat diarrhea – that morning.

As investigators continue to probe the property, Arenas Del Mar, where rooms can go for more than $1,300 a night, has slashed its prices.

Reservations that had cost $1,330 per night are down to $998, and even its cheapest rooms are down from $790 to $593, according to the Arenas Del Mar booking page.