Returning from Canada, Melissa Etheridge was busted for drug possession in North Dakota after her tour buses were stopped by U.S. Customs and Border Patrol.

The arrest occurred August 17, TMZ reports, but the media is just getting a whiff of the incident now.

When a K-9 unit detected possible drugs, border agents searched the bus and found marijuana oil.

Etheridge claimed that she uses the oil to manage pain from cancer, noting that medical cannabis is legal in her home state of California. Unfortunately, it is still illegal in North Dakota.

The singer was booked for possession of a controlled substance and pleaded not guilty.

Etheridge was diagnosed with stage 2 breast cancer in October 2004. Following a lumpectomy and five rounds of chemotherapy and radiation, she has not relapsed.

The Grammy winner has previously praised weed for helping her write music, destress, and forget about our current president. She has even launched her own line of pot products.

Currently on tour, Etheridge will sing the National Anthem today at the Chiefs vs. Steelers game at Kansas City's Arrowhead Stadium in support of the "Crucial Catch" campaign, which aims to raise awareness about catching cancer early. The American Cancer Society will honor local cancer survivors during the game.