The antidote filled the man's nostril.
The purple faded. Then it came back. Kowalski's heart raced.
"We only gave him one, and he needs another!" she called to a security guard in McPherson Square Park, a tranquil patch of green in one of this city's roughest neighborhoods.
"He's dying," said a bystander, piling on as tension mounted around lunchtime one recent weekday.
"Where is the ambulance?" a woman begged.
Kowalski dropped the second syringe and put her palm on the man's sternum.
Knead. Knead. Knead.
She switched to knuckles.
Knead. Knead. Knead.
Then a sound, like a breath. The heroin and methamphetamine overdose that had gripped the man's body started to succumb to Kowalski's double hit of Narcan.
With help, the man, named Jay, sat up. Paramedics arrived with oxygen and more meds.
Death, held at bay, again.
Kowalski headed back across the park, toward the century-old, cream-colored building where she works.
"She's not a paramedic," the guard, Sterling Davis, said later. "She's just a teen-adult librarian -- and saved six people since April. That's a lot for a librarian."
Libraries and a public health disaster
Long viewed as guardians of safe spaces for children, library staff members like Kowalski have begun taking on the role of first responder in drug overdoses. In at least three major cities -- Philadelphia, Denver and San Francisco -- library employees now know, or are set to learn, how to use the drug naloxone
, usually known by its brand name Narcan, to help reverse overdoses.
Their training tracks with the disastrous national rise in opioid use
and an apparent uptick of overdoses in libraries, which often serve as daytime havens for homeless people and hubs of services in impoverished communities.
In the past two years, libraries in Denver, San Francisco, suburban Chicago and Reading, Pennsylvania have become the site of fatal overdoses.
"We have to figure out quickly the critical steps that people have to take so we can be partners in the solution of this problem," Julie Todaro, president of the American Library Association, told CNN.
Though standards vary by community, the group is crafting a guide for "the role of the library in stepping in on this opiate addiction," she said. It will include how to recognize opioid use -- short of seeing someone with a needle -- and how to address it.
McPherson Square Library, where Kowalski works, has a wide, welcoming staircase punctuated by tall columns. It sits in the Kensington community, where drugs and poverty lace daily life.
Residents drop into the McPherson branch with questions about doctor visits and legal matters. Children eat meals provided by library staff and play with water rockets in a Science, Technology, Engineering, Arts and Mathematics program.
Kensington doesn't host a civic institution, like a university, or a major company, said Casey O'Donnell, CEO of Impact Services
, a Kensington community and economic development nonprofit.
"In the absence of those things, the anchors become things like the library," he said.
In recent months, so-called "drug tourists" -- people who travel from as far as Detroit and Wisconsin seeking heroin -- started showing up in Kensington, which boasts perhaps the purest heroin on the East Coast, library staff and authorities said.
Heroin users camped out in McPherson Square Park and shot up in the library's bathroom, where nearly a half-dozen people overdosed over the past 18 months, said branch manager and children's librarian Judith Moore.
The problem got so bad that the library was forced to close for three days last summer because needles clogged its sewer system, said Marion Parkinson, who oversees McPherson and other libraries in North Philadelphia.
Since then, patrons have had to show ID to use the bathroom, she said. The library in October hired monitors to sit near the bathroom, record names on a log and enforce a five-minute time limit.
Before the crackdown, library staff last spring discovered one man in the bathroom with a needle in his arm, Moore recalled. He toppled over and started convulsing.
"I heard his head hit the floor," she said.
A city employee had left a dose of Narcan at the library. But the staff didn't know how to use it. After that, Parkinson set out to get them trained.
'It's not normal'
At 33 years old, Kowalski wears oversized sweaters and too-big glasses. She reads nonfiction about World War II and zones out on Netflix. She settles into work mode by listening to pop music on her train ride to work.
She chose to work at the McPherson branch because she thought her own experience could help students who flock there after