In conclusion, K2 paper, or prison paper, refers to paper infused with the synthetic drug K2, which has gained popularity in prisons across the United States. Inmates ingeniously smuggle the drug by saturating paper items with liquid K2 and tearing them into smaller pieces for smoking or consumption.

K2 is a synthetic drug that's a clear, odorless liquid and is apparently being sprayed on letters mailed to inmates. "They can rip up pieces of paper and smoke it, which is what I'm guessing they're probably doing, or they can ingest the paper," said Mitchell West, Medical Director at Allegheny Health Network's Addition Services.

One Texas corrections official declared K2 “ the new drug of choice, inside and outside of prison," in 2017. Soaking paper in liquid Suboxone and mailing it to inmates is a common smuggling method. Sometimes the drugs are mixed with ink or crayon wax and delivered as handwritten mail or children’s drawings.

K2 begins as a liquid that can be sprayed on any kind of paper product, like letters. Inmates then smoke or ingest pieces of the soaked paper, or sell it to other inmates.

Soon, federal prisoners will not be able to receive any paper correspondence but will have to read letters on “kiosks” in housing units. Bureau of Prisons (BOP) officials say the move is needed in order to stop the flow of drugs coming in through the mail, including synthetic marijuana known as K2.