In a haunted world of heroin and hurt and heartless hustles, located between a dusty brickyard and rusty railroad tracks along the border of Chicago and blue-collar Cicero, Steve Kamenicky is the go-to guy.

Longtime addicts and novice users seek out Mr. Kamenicky, known as Pony Tail Steve, sometimes in the middle of the day, other times deep into the night. They go to him, usually in a panic, desperate for an injection for a fallen buddy or lover of what some call a miracle drug. They hurry over the paving bricks that Mr. Kamenicky neatly laid to lead the way to his tent, pitched among the tall weeds and trees in one of a string of small encampments of the homeless on the edge of the brickyard.

Mr. Kamenicky, 52, is not a dealer. His own heroin addiction is much too strong. He shoots every $10 bag of heroin he can.

But his fellow addicts consider Mr. Kamenicky a savior.

“I’ve saved more people than the paramedics,” he boasted the other evening as he sat in a Cicero parking lot, his long, salt-and-pepper ponytail snaking down his back.

The drug he administers to fellow heroin users is called Naloxone or Narcan, its brand name. Mr. Kamenicky estimated that in the last few years he had brought back from the deadly depths of heroin overdose at least 35 addicts — in abandoned buildings, crack houses and around kitchen tables.

Naloxone, which is injected, reverses the effects of an opiate overdose. A drug that was a few years ago given by doctors and paramedics, Naloxone is now directly dispensed to drug users like Mr. Kamenicky, who are trained by the Chicago Recovery Alliance and receive Naloxone through a doctor-supervised program. The effort is part of an up-from-the bottom movement in the struggle to rescue those addicted to heroin and other opiates.

“It saves lives,” said Dr. Virgilio Arenas, who leads the addiction division at Northwestern Memorial Hospital. “Naloxone is an effective antidote. It works within minutes once administered.”

Mr. Kamenicky receives Naloxone free, as do drug users across the city, from the alliance, a nonprofit needle-exchange and H.I.V.-prevention program. The alliance also dispenses fresh syringes, condoms and other paraphernalia to users in the hope that they will stay alive long enough to make “any positive change,” the group’s mantra.

Dr. Arenas said there were similar “harm-reduction” projects in Milwaukee, New York and other cities where needles and Naloxone were distributed.

Not everyone endorses the effort. “Some people in the addiction field feel it might foster more drug use,” Dr. Arenas said, adding, “but I don’t think people will use more because they have the antidote. I favor the harm-reduction approach.”

Anecdotal evidence suggests that the Naloxone campaign is saving lives in the Chicago metropolitan area, which led the nation in heroin-related hospital emergency-room visits from 2004 to 2008, according to a recent study. The Illinois Consortium on Drug Policy at Roosevelt University found that there were 23,931 such cases during that period, 50 percent more than were reported in New York City, which ranked second.

Dan Bigg, director and co-founder of the Chicago Recovery Alliance, said the group had collected about 2,000 reports of overdose reversals since 2001 when it began widely dispensing Naloxone to addicts — and even to family members, including one Lake Forest mother, who keeps a vial in her home in case her heroin-addicted daughter has another overdose.

“She wants a living daughter,” Mr. Bigg said, “despite whatever potential challenges she might bring in terms of struggling with drugs or education or marriage or anything else.”

Mr. Bigg said he had used Naloxone to reverse five overdoses. Greg Scott, a sociology professor at DePaul University and the recovery alliance’s research director, said he had reversed 24 overdoses, including a case two years ago when he used Naloxone on Mr. Kamenicky.

For years, Professor Scott has been documenting life in the “Brickyard,” Mr. Kamenicky’s encampment. In the last three years, he said, he has interviewed up to 300 suburban residents who come to the Brickyard to use the heroin they buy in surrounding neighborhoods before slipping back into mainstream society.

Mr. Scott said he had interviewed suburban housewives, hard-driving commodities traders and “weekend warriors,” who shoot up and get a thrill from hanging out at the Brickyard. He said the traders were the least responsive to his offers of Naloxone.

They don’t want to admit they might have a problem,” he said.

Mr. Scott, 42, has also been on the other end of the needle. He said he was addicted to opiates until a few years ago, overdosing on three occasions. Each time, he said, the overdose was reversed by Naloxone.

“It really is a kind of miracle drug,” he said.

Not everyone is as lucky as Mr. Kamenicky or Mr. Scott. In 2008, the most recent year for which statistics are available, there were 390 opiate-related overdose deaths in Cook County, up from 280 in 2007, said Dr. Nancy Jones, the Cook County medical examiner.

Dr. Jones said it was impossible to say how many might have been saved by Naloxone and not “end up on my table.”

The Chicago Recovery Alliance dispenses Naloxone from a fleet of silver panel trucks, which are parked in designated spots around the city every day. One truck recently sat baking in the sun at 61st Street and Calumet Avenue. Cheryl Hull, an alliance employee, has dispensed syringes, advice and compassion from the trucks for nearly 17 years.

Ms. Hull said she gave addicts a bottle of Naloxone and a DVD instructing them on its use. For those without DVD players or places to watch, Ms. Hull pops a disc into the truck’s portable player. Many people do not take the time to watch the instructions, she said, adding that young suburbanites were the most reluctant to linger and learn because they were afraid of the police and city crime.

On Wednesday night, Mr. Kamenicky sat on a plastic bucket, waiting for the alliance truck at a Cicero parking lot. He said it felt good to save a life, to give someone a second chance.

“I’ve only lost one person,” he said.

The victim, he said, was his boss at a suburban print shop. The man started snorting a $10 bag of heroin and then lost consciousness. Mr. Kamenicky ran to find his miracle drug.

“But somebody took it,” he said. “I tried to get some other people to help me, but they were too busy getting high. They couldn’t be bothered.

“By the time I found some Narcan, it was too late. I gave him a shot, but he was already dead.”