The heroin has been linked to at least 49 overdoses in Camden, authorities said.
CAMDEN -- Last week, first responders rushed to dozens of calls for people overdosing on heroin. Thankfully, each was revived with a dose -- or sometimes two or more -- of the opiate-blocker naloxone, also called Narcan.
Heroin packaging stamped with 'Batman.' According to New Jersey State Police, those overdose victims only reported using one kind of heroin. It's packed in a strip of blueish wax paper stamped with a "Batman" label.
Between Tuesday and Saturday morning, Cooper University Health Care ambulances in Camden treated at least 49 overdoses. The number of overdoses since Saturday was not available Monday from the hospital or law enforcement sources.
The New Jersey State Police's Regional Operations and Intelligence Center is working with police in Camden and around the county, as well as the Drug Enforcement Administration, to track the spread of the drug.
So what is this Batman brand heroin and where did it come from? Here's what we know about the superhero-branded drug that authorities say is super-dangerous.
Why is it so lethal?
Timothy McMahon, a special agent in the New Jersey Division of the DEA, said his division is still awaiting results from the State Police testing of the heroin.
"Probably it comes down to the people who are cutting it doing it wrong," McMahon said. That might mean that a dealer did not cut the pure heroin with as much of a harmless substance -- chalk, baby formula, ground-up drywall -- as usual. If it's more pure than users are accustomed to, their regular dose could kill them.
It may also mean that a dealer added something to the heroin to increase its potency. Fentanyl, a painkiller that is much stronger than heroin, is an additive that has been responsible for more and more overdoses in New Jersey. It is up to 50 times more powerful than heroin.
"When the lab results get back, we'll have have a better idea," McMahon said.
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Is it the same kind causing overdoses in other states?
McMahon said it's hard to tell if the dangerous heroin in the Camden area is the same kind or uses the same additive as the heroin that is causing dozens of overdoses in several other states.
A recent spike of overdoses in Cincinnati -- 174 in six days -- is due to heroin cut with carfentanil, an opioid used to tranquilize large animals including elephants, the Chicago Tribune reported. It's 100,000 times more potent than morphine, and USA Today reported officials believe it's being smuggled in from China because there are so few places in the U.S. that would have it on hand.
There have also been rashes of overdoses in Kentucky, West Virginia, and Illinois in recent days, but authorities have not said whether carfentanil is to blame.
McMahon said he hasn't heard of Batman-stamped heroin being found in any other parts of the country, but sometimes copycat dealers will get a Batman stamp of their own after users seeking an intense high start asking for it.
Where is it coming from?
McMahon said that while Camden may be ground zero for the Batman heroin overdoses in South Jersey, it likely isn't being made there.
"It's not a big source city. A lot of times it's brought in from other areas," McMahon said. A lower-level drug dealer might go to Paterson to get a large amount of heroin and then package it for sale in Camden, he said.
The Courier-Post reported that State Police sent an alert to law enforcement agencies warning that the overdoses began when people used free samples of heroin stamped with Batman that was sold in Camden.
The report said that the overdoses began after Batman heroin started being sold in Camden in the last few weeks, but the brand has been seized in the last two months in other areas in South Jersey including Voorhees, Galloway, Runnemede, Gloucester City, and Williamstown.
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Why 'Batman'?
Flynn said that there doesn't appear to be any rhyme or reason to the name or logos dealers choose to stamp on their heroin packages. Police have seized packages stamped with names ranging from Donald Trump to Obamacare and Prada.
A batch of fentanyl-laced heroin stamped "Bud Light." "They brand their particular heroin. It's a kind of marketing strategy, sadly," he said. Users who liked a product can ask for it again, by name.
An unintended consequence of the stamping is that it helps law enforcement link overdoses to dealers and warn the public to avoid a brand.
That's the goal of the Drug Monitoring Index, a division within the State Police Regional Operations and Intelligence Center. Staff there works with hospitals and local law enforcement to monitor overdoses and what brands are associated with them, Flynn said.
Why did police release info about the Batman brand?
Law enforcement face a dilemma when considering whether to release information on certain brand of heroin linked to overdoses.
A recovering addict who contacted NJ.com after an article Sunday about the overdoses said that police and media should stop reporting the stamps linked to overdoses.
"If I were still using just seeing that article would make me go in search of Batman," he said. "If someone overdosed on this then to me that means it's good heroin!"
But both McMahon and Flynn said that it is their responsibility is to make the public aware of an especially deadly drug.
"We do understand that if we identify it, it's going to draw some people to it," Flynn said. "But if we have information that a brand of heroin is known to cause overdoses, it's important for us to put it out there... It may make a few people say, 'hey, I'm not taking that.'"
There is also a chance that the information may make users more careful when they take that brand, he said. They may decide to use less, he said, or use only with friends so that someone could administer Narcan or call an ambulance if he or she lost consciousness.
Rebecca Everett may be reached at reverett@njadvancemedia.com. Follow her on Twitter @rebeccajeverett. Find NJ.com on Facebook.