Ted Galaty, owner of Hemp Maze Minnesota, was sending samples of his first indoor-grown hemp crops to a Colorado laboratory to test their tetrahydrocannabinol (THC) level, per U.S. Department of Agriculture requirements.

His package wasn’t returned to sender. It was seized by law enforcement.

Private parcel companies have refused to deliver or tipped off law enforcement about hemp packages that look and smell like drug cannabis, a federally illegal substance. Therefore, experts have advised shipping hemp through the U.S. Postal Service, as the agency must abide by federal law.

USPS requires people shipping industrial hemp to have a license from a state’s Department of Agriculture authorizing the licensee to produce industrial hemp and results that show the hemp’s THC concentration not exceed 0.3%. That can be a problem for cultivators like Galaty as tests are not always available in state, results can vary from laboratory to laboratory—and so can costs. Determining legal shipments of hemp and illegal shipments of marijuana is also an extra expense for the post office.

“I’m not saying they’re in the wrong,” he told The Post Bulletin. “We just need to work out a better way to do this.”

Galaty contacted the USPS’s Contraband Investigation & Interdiction Team, and his package was resealed and ultimately sent to Colorado.

Read More: Lessons Learned from Hemp Shipments Gone Wrong