David Witherspoon can't get a certain cold concrete tunnel out of his mind. It's where his 17-year-old son Keith died.
Keith is one of 18 North Texas teens to overdose on heroin since January 2005, CBS News correspondent Kelly Cobiella reports.
Asked if he thought his son knew he was taking heroin, Witherspoon says no.
"He didn't know; none of these kids know at that age," he says.
The kids know it as "cheese": nighttime pain reliever crushed and laced with black tar heroin. It sells for $2 a hit, and it's become the new classroom high. Though kids are dying, kids are buying: Arrests for possession in Dallas schools have jumped 82 percent this year, with dealers as young as 11.
"I see a lot of people doing it. In class, everywhere," says Victor, who started using in middle school ... snorting cheese thru a hollowed-out pen when his teacher turned her back.
"You take the top, then you take this, then you sniff it," Victor says, demonstrating.
Only 16, Victor is now in rehab for the second time in seven months after nearly dying three weeks ago.
"The next time I did some, I didn't feel high with just one line. So I needed to use more to get high," he says.
Five years ago, the state health department paid for 19 North Texas teens to be treated for heroin addiction. Only six months into this fiscal year, that number had grown to 135 teenagers, a 600 percent increase, at more than 10 times the cost.
Treatment centers like Dallas' Phoenix House are feeling the strain. There's not enough money to fill all of the beds, and they've had to cut treatment time from six months to six weeks.
"We've got a tragedy," says James Capra, special agent in charge at the Dallas Drug Enforcement Administration. Capra is trying to stop the problem before it spreads beyond Texas.
"Kids are saying 'It's cheese, it's cheese.' It's heroin. It's deadly, deadly heroin."
North Texas schools are scrambling to get the word out to parents. The Witherspoons wish they'd known more about cheese.
Asked if they thought they could have done more as parents to prevent the tragedy, Dave Witherspoon says, "You always question that."
Now the Witherspoons hope sharing their loss will prevent dark days for another family.