INHALANTS SEEP BELOW PARENTS' RADAR Diane Stem of Old Hickory, Tenn., vividly remembers the day she was called home by her distraught husband and daughter: Her 16-year-old son, Ricky Joe Stem Jr., had been found dead in the house with a plastic bag over his head. He had been sniffing Freon from the house's air-conditioning system. Marissa Manlove of Indianapolis got a call from a friend in June 2001 who told her that her 16-year-old son David Jefferis Manlove had dived into a swimming pool and not come up. The teenager died after breathing from a can of computer duster, using the nozzle as a straw to suck the chemical toluene inside. Toy Johnson Slayton of St. Simon's Island, Ga., remembers the police coming to her home in December 2001 after her 17-year-old son Johnson Bryant was found dead in his truck after going into cardiac arrest and hitting a tree. A can of butane and a surgical glove were found with the body -- police told her they believed her son had been "huffing." "I looked at the man and said, 'What does that mean?'" she said. "I am so angry because this was not on my radar screen. We had discussed the dangers of drugs and alcohol, but never, ever in my wildest dreams had I known to look at a can of butane with fear." A hidden epidemic is gaining momentum in America, experts say. Children as young as fourth-graders are deliberately inhaling the fumes of dangerous chemicals from a variety of household and office products. Inhalants, as they are known, are widely available and hard to detect, and are fueling a dangerous trend: The most reliable annual survey of drug use among children has found that inhalants are the one group of drugs in which abuse is on the rise. The chemicals travel rapidly to the brain to produce highs similar to alcohol intoxication. Unlike the effect of alcohol, these highs disappear within minutes, making it hard for parents to detect the abuse. The products, which can range from gasoline to cigarette lighter fluid, cleaning supplies to adhesives, are often highly toxic and addictive. New brain imaging research has shown that the chemicals can produce lasting changes in the brain, as well as heart, kidney and liver damage. The new brain imaging research also shows that different inhalants affect different parts of the brain, which might be why children report preferences. "Some kids like to huff acetone, some like to huff toluene and some like butane," said Stephen Dewey, a researcher at the Brookhaven National Laboratory in New York. Some indications suggest the problem may be growing faster among girls. Overall, nearly one in five eighth-graders has tried an inhalant, usually by breathing from a rag or a bag doused with the chemical. The increase in abuse has tracked a sharp drop in youngsters' perceptions of the risks of inhalants, said Lloyd Johnston, a researcher at the University of Michigan who helps conduct the annual "Monitoring the Future" survey of eighth-, 10th- and 12th-graders. Parents seem to know little about the trend. "It completely caught us off guard," said Diane Stem of Ricky's death. "He was a great kid, a great athlete; we have a loving supportive home; we had warned him about drugs and alcohol, but we didn't know to warn him about inhalants." In retrospect, these parents say, they ought to have been more worried. "Not every family has crack cocaine under their sinks, but every family has cleaning products under their sinks," Stem said. Data show that inhalant abuse among children is growing in all parts of the country. Use is highest among whites, followed closely by Latinos, and is lower among blacks. The problem afflicts children from all socioeconomic backgrounds, and from families with both high and low levels of parental education. But stereotypes about who abuses inhalants and the stigma associated with the practice have kept many parents from believing that the problem could affect them and blinded them to warning signs, said Slayton, Johnson Bryant's mother. "Looking back, there was an episode where I went in a playroom and found a surgical glove and thought, 'What is the cleaning service leaving a glove for?'" she said. Her son Johnson was filling the gloves with butane and inhaling from them. "He had a heavy cough. He had bouts of belligerence. The stigma of inhalants is what kept me from being aware."