Each morning as Rosie Silvio walks into Erskine Park High School in Western Sydney, she sees smoke waft from the window of the bathrooms.
"You'll see a group of kids walk out and you'll kind of know they were all in there vaping," the year 11 student said.
The bathrooms at this school are locked when classes are on, and monitored at lunchtimes to crack down on vaping.
Erskine Park High is not alone with health and education researchers finding a rising number of school students are vaping in New South Wales.
Director of the prevention education and research unit at the Westmead Hospital, Professor Smita Shah, said: "It is a public health crisis."
Researchers from the Western Sydney Local Health District (WSLHD) conducted a survey on vaping at Erskine Park High School, in which 19 students from years 7 and 10, six parents and 24 teachers took part.
The teachers estimated between 20 and 60 per cent of students were vaping and that they were doing so openly in classrooms and on playgrounds.
"We're certainly noticing a bit of an edge to some of our students," the school's principal, Brenda Quayle, said.
NSW Health estimates the nicotine in one vape can equal 50 cigarettes.
Some of the students surveyed said they were drawn to vapes because they saw older friends, family and social-media influencers do it and thought it was cool.
Others said they wanted to rebel, considered vapes safer than cigarettes, or that they liked the fruity flavours.
"There's all of these things that are making them incredibly appealing to young people," Ms Quayle said.
"And, because we don't know the long-term health impacts, I'm very concerned in the next 30, 40 or 50 years' time, that this will be the next big health crisis."
It's illegal to sell a vape to anyone under 18 years of age in New South Wales and, since October 2021, vapes containing nicotine can only be bought with a prescription.
However, this week, an ABC Four Corners investigation found a thriving black market for nicotine vapes.
"People sell them everywhere," Rosie Silvio said.
"As soon as one person gets one, people are going to ask that person to go and get them some.
"So that person becomes, I guess, the supplier."
Ms Quayle said students were buying vapes in bulk online and then distributing them.
"We're having conversations with a lot of people around, 'You understand that could be considered supply of an illegal substance, essentially'," she said.
Philip Morris International Australia, the tobacco giant that's pledged to shift away from cigarettes and towards e-cigarettes, said the illegal sale of vaping products was a "legitimate concern for schools, parents and the wider community".
"These products are illegally imported and distributed," a spokesperson said.
"Australian authorities … are equipped with robust powers to address youth access and seize illegal products. However, at present, it is clear that not enough is being done to enforce the law."
NSW Health and the Department of Education acknowledge vaping is a problem in schools across the state.
Since the beginning of the year, NSW Health has conducted raids that have seized illegal e-cigarettes and liquids containing nicotine with a street value of more than $1 million.
"People think they are simply flavoured water but, in reality, in many cases they are ingesting poisonous chemicals that can cause life-threatening injuries."
In May, NSW Health released a range of educational resources on vaping, targeting students, teachers and parents.
In Western Sydney, researchers have expanded their study to five more schools to try to gain a greater understanding of the problem and how to address it.
Ms Quayle worries the response will come too late.
"I think the horse has bolted to be honest," she said. "Unless there's a real strategy to prevent the online purchase, I think it will be something that's almost impossible to stop."
Rosie Silvio believes vapes have found their way into many households without parents knowing.
"You might not want to believe that your kid vapes, but you just gotta double check and make sure to help stop it," she said.
