He underwent hospital treatment at the end of August for nausea and laboured breathing after using e-cigarettes for more than 18 months.
"I'm 18 years old. My lungs are like a 70-year-old's," he told CBS while in hospital. “My lungs will never be the same."
In a statement on Friday, Juul said it had “never marketed to youth” and argued its products were meant to help adult smokers quit traditional cigarettes.
The Illionis lawsuit claims the company used advertisements and social media campaigns to encourage young people to use e-cigarettes but never full disclosed that their products contained dangerous chemicals.
More than 450 cases of lung illness potentially linked to vaping have been reported in the US, according to the Centres of Disease Control and Prevention, with at least six confirmed deaths in connection to vaping-related illnesses.
Mr Hergenreder said he first started vaping “because everyone else was doing it” and was unaware of any health risks from e-cigarettes.
He said he progressed from vaping over-the-counter e-liquids to THC, the main psychoactive component in cannabis, which he got from a drug dealer.
Mr Hergenreder said later began to develop shivers and started vomiting “every day for three days” before he went to visit a doctor.
When doctors took an X-ray of his lungs, they discovered “significant damage” and he was admitted to hospital.
"If his mum had not brought him to the hospital within the next two to three days, his breathing could have worsened to the point that he could have died if he didn't seek medical care," Dr Stephen Amesbury, one of the doctors who saw Mr Hergenreder, told CNN.
"It was severe lung disease, especially for a young person. He was short of breath, he was breathing heavily.
“It was very concerning that he would have significant lung damage and possibly some residual changes after he heals from this.”
The lawsuit against Juul has accused the company of sometimes relying on indirect advertising to children, including employing social media users with huge followings to promote Juul products on Twitter and Instagram.
The legal case also names a gas station in Waukegan, Illinois, as a defendant, accusing it of regularly selling Mr Hergenreder nicotine-based Juul products when he was under the legal purchase age of 18.
Antonio Romanucci, Mr Hergenreder’s lawyer, said: "To put it mildly, Adam didn't stand a chance to avoid getting hooked on these toxic timebombs.”
A federal investigation into vaping-related lung illnesses is ongoing and has not identified the cause of the illnesses– although a number of patients have reported using e-cigarettes with cannabis-related products, such as THC.
Earlier this week, Donald Trump announced his administration would ban flavoured e-cigarettes following the spate of illnesses.
However, Mr Trump appeared to take a less aggressive tone on Friday evening, when he tweeted: “While I like the Vaping alternative to Cigarettes, we need to make sure this alternative is SAFE for ALL!
“Let’s get counterfeits off the market, and keep young children from Vaping!"
Kevin Burns, Juul’s CEO, warned last month that people who do not already smoke should not use his company’s products.
"Don't start using nicotine if you don't have a pre-existing relationship with nicotine," he said. "Don't use the product."
Agencies contributed to this report
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