(CNN) Most 20-year-olds might take on a part-time job when they need extra cash. But this Wisconsin man was a bit more criminally ambitious, police say.

Tyler Huffhines, 20, has been arrested after being accused of running an illegal vaping business , loading the cartridges with illegal cannabis-derived THC oil and selling the products for about $22 each, authorities said in a news conference Wednesday.

It wasn't just a side hustle.

Huffhines had been running the operation for almost two years, since January 2018, and he had about 10 people working for him, authorities said.

Reached by CNN, Huffhines' lawyer, Mark Richards, refused to comment.

Huffhines, who is not yet formally charged, faces multiple felony charges: manufacturing/delivering THC, possession with intent to sell, maintaining a drug trafficking place and misappropriation of personal identifying materials.

Thousands of cartridges per day

Kenosha County Sheriff David Beth described the operation as a sophisticated one.

Huffhines' employees even had time cards and were paid 30 cents per cartridge filled, Beth said. The employees are believed to have worked in an assembly line, filling empty vaping cartridges with THC oil from California, Beth said.

Authorities said the employees filled about 3,000 to 5,000 cartridges a day, according to CNN affiliate WITI

Authorities said they found more than $300,000 worth of THC oil in the condominium where the operation was being held -- in an area that Beth called "a beautiful subdivision." Beth said he is unsure how much Huffhines actually made off the business.

The investigation continues

Police are investigating others who may have been involved, and the list "seems to keep growing each day," Beth said.

"I'm glad we caught it," he said. "If this one is out there, there's other ones out there."

The THC oil is currently being tested and police say they aren't sure whether the oil was cut with other drugs.

The arrest comes amid increasing scrutiny around vaping

A Kansas woman died Tuesday from lung disease related to vaping, making her the sixth person in the United States to die of these causes in recent weeks.

Earlier this month, the Centers for Disease Control and Prevention reported there are at least 450 possible cases of severe lung disease that could be caused by vaping , though officials aren't sure what, exactly, ties them together.