Amid a national health crisis over vaping-linked respiratory illnesses, educators across the country are taking extreme measures to stop students from puffing on e-cigarettes.

But not in New York City’s public schools.

While others are going as far as removing bathroom doors and expelling students caught just once with e-cigarettes, the nation’s largest district is taking a comparatively lax approach.

Principals say the Department of Education has equipped them with paltry punishment options for kids caught vaping, and school safety agents don’t even issue “warning cards” to vapers.

“School leaders have been communicating their dissatisfaction with how the discipline code addresses vaping,” said Craig DiFolco, spokesman for the Council of School Supervisors and Administrators. “The recent changes to the discipline code have further eroded principals’ discretion.”

“Vaping” and “e-cigarettes” were added to the DOE’s list of “Level 2” infractions earlier this month, the agency said, with punishments ranging from a meeting with the student to being kicked out of class.

“You cannot suspend for vaping,” said one middle-school principal. “If a kid kicks up his feet in class and smokes a cigarette … you can call the parent. That’s about it.”

There have been 64 reported cases of vaping-related respiratory illnesses statewide and 14 in New York City. The Centers for Disease Control has counted 380 confirmed and possible cases nationally linked to vaping nicotine and marijuana.

In a 2018 survey released Tuesday, 13,000 New York City middle-school students admitted to using e-cigarettes in the previous 30 days.

Across the US and in NYC private schools, administrators are cracking down.

Ten districts in New Jersey, plus high schools in Long Island, Ohio and Illinois, have installed vape detectors in student bathrooms, CNN reported.

Along with restroom sensors, Staten Island’s Monsignor Farrell HS is installing facial-recognition cameras on bathroom outer doors and adding magnetic locks that open with chip-equipped student ID cards to track when students enter and how long they’re inside.

“The deans are excited that I’m giving them a tool with teeth,” the Catholic school’s president, Lou Tobacco, told The Post. “No school is immune from this problem. We can’t keep our heads in the sand.”

The system for the 800-student school costs less than $15,000, Tobacco said.

In public schools, the NYPD’s school safety agents can confiscate the easily concealed vaping devices, but it’s up to the principal to discipline students.

“Students smoke marijuana on school grounds, and School Safety Agents, due to new disciplinary guidelines, can only issue toothless ‘warning cards,’” said Gregory Floyd, president of the Teamsters Local 237 union that represents the agents.

“Vaping and e-cigarettes present yet another challenge to keeping students out of harms’ way.”

DOE spokeswoman Miranda Barbot said, “The health and well-being of our students is our top priority, and in partnership with the City’s Health Department, we’ve shared information with schools, students, and families on the risks of vaping,”