PORTLAND, Ore. -- Teens are teaming up with Multnomah County and they’re going undercover.

Their mission is to bust stores that sell tobacco to people under the legal age. Oregon law changed this year. Now you have to be 21 to buy tobacco and vape products.

The teams are part of a new program that just started last week. About ten 18-and 19-year-olds are employed in the on-call position so far. They’ve already visited almost 70 stores. Twelve percent of those stores failed the test. Now, the nearly 800 other licensed tobacco retailers in Multnomah County will have to be a lot more careful with tobacco sales.

That’s because walking Portland’s streets are teens like Michael. That's not his real name, and we're not showing his face because he's working undercover.

“Today, I'm walking into a store, asking to buy tobacco, telling them my real age, and if they sell to me, they sell to me, if they don't, they don't,” Michael explained.

"I feel like tobacco needs to be for adults and not have people get cancer at young ages. People start at young ages and that's not good,” said Michael.

Research suggests more than one in five 11th-graders use some form of tobacco in Multnomah County.

“Unfortunately Multnomah County has a track record of selling tobacco and nicotine products to underage minors,” said Kari McFarlan, who supervises the Tobacco Control and Prevention Program within the Multnomah County Health Department.

We can't show McFarlan’s face either because she goes out with the teenage inspectors. On this particular day, the team got a hit.

“Walked inside the store, asked for Marlboro Golds and he sold to me without asking for ID,” said Michael.

He said he knows he alone won't stop all illegal sales. He said teens are all over social media talking about which stores will sell them cigarettes.

But he has a message to his fellow teens and young adults.

“One, it's too expensive; two it's harmful. Why would you do that?" Michael asked.

Store owners will face a $500 fine if any of their employees sell tobacco to someone under 21.

A second offense could mean their tobacco retail license is pulled.