Owners of stores that sell drug paraphernalia, known as head shops, say their business is growing as more states legalize the medical and recreational use of marijuana. These stores stay out of trouble with the law by saying their products are for tobacco use only, USA Today reports.

The stores sell products including water pipes, rolling papers and vaporizers. Special Agent Erin Mulvey, spokeswoman for the Drug Enforcement Administration, said that under the federal Controlled Substances Act, head shop owners cannot be arrested for selling drug paraphernalia because they can claim their products are for tobacco use. “Our laws don’t just focus on paraphernalia, but the drugs themselves,” she said.

According to a Pew Research Center survey released earlier this year, 12 percent of Americans say they have used marijuana in the past year. Among people younger than 30, the survey found 27 percent say they have used marijuana in the past year, at least three times the percentage in any other age group.