It's the newest trend for young people looking for a cheap high - teenagers breathing in a dangerous gas. And you won't believe where they're getting it - from your home's air conditioning unit.
You can see the effects in videos posted on the internet. People laughing uncontrollably, stumbling over, or just sitting in a dazed stupor.
"I still can't believe he's not here," says Mona Casey of Naples, Florida. She was shocked when she learned her son Charles was inhaling, or huffing, air conditioning refrigerant.
"When Charles huffed the refrigerant it knocked him out. When he came to, he asked. ‘What was that? I'm never ever going to do that again,' " said Casey.
But just two weeks later, Mona's husband made a startling discovery at the side of the house.
"He saw somebody through the door, hunched over by the neighbor's air conditioning unit. It was Charles. He had apparently been using the neighbor's AC unit to get high. When he turned him over, he made this gurgling sound," said Casey.
Charles died after two days in the hospital with no brain activity. The cause of death: "poisoning by inhalation of Freon," a brand of air conditioner refrigerant. He was just 15 years old.
And he's not the only one. Tragically, deaths from inhaling the gas in air conditioners have been happening across the country.
"It's essentially like playing Russian roulette. You never know if the next time you're going to do this stuff is going to be the last time you're able to do it," said Dr. Lewis Nelson, an emergency physician who specializes in medical toxicology at NYU Medical Center.
Home surveillance footage, obtained by INSIDE EDITION shows teens actually tapping into a neighbor's AC unit. The footage shows the gas spraying out. They capture the gas in a bag and inhale it right on the spot. Seconds later, they stagger away.
"This is a real hidden danger," says Rick Hennig, a certified air conditioning technician at Universal Supply Group in New Jersey. He urges parents to check for signs of tampering.
He advises homeowners to look for missing caps and any issues with cooling. "If it's getting hot in the house and it's happening over and over again, it's either leaking or somebody's taking it out."
He says homeowners can solve the problem by having a professional air conditioner specialist install locking caps over the valves.
Since her son's death, Mona Casey has been on a crusade to warn teens about the dangers of this cheap high. "I heard that some of those boys my son learned how to huff with, were still doing it. Even after they attended my son's memorial service. Like, what else do you need to get it through your brain that this something you're not supposed to do."
A locking cap can be installed on the valve of an outdoor air conditioner to prevent someone from accessing the deadly refrigerant.
To learn more about Mona Casey and the work she's doing to protect kids from accessing refrigerant, go to uproarorg.org.
Safety experts say, to prevent someone from tapping into your air conditioning unit, homeowners should safeguard their outside air conditioning units.
They say the absolute best way to prevent anyone from accessing your refrigerant is to have the tamper resistant locking caps installed by a professional air conditioning technician.
Other options can include putting a fence around the unit with a padlock and in some cases, placing your air conditioning system atop your roof, preventing others from getting close to it.
For more information about the refrigerant locking caps, go to noventcaps.com.