A bill making its way through the state Legislature would require medical marijuana sold at state-regulated dispensaries to be tested for mold, disease-causing bacteria and “other harmful adulterants.”

MORE: State Lawmakers Move On Medical Marijuana Regulations

The testing bill raises some questions about transparency in the medical marijuana industry and quality of its products. Hope Jones is chief scientific officer for C4 Labs, a cannabis testing firm in Mesa. She described to Senate members one scenario where she found a medical marijuana product was a dud.

"We tested six bottles, and all but one were completely negative," Jones said. "This parent paid nearly $1,000 for this medicine, and it was a fraud."

Here to talk about this is Will Humble, former director of the Arizona Department of Health Services and currently serving as executive director for the nonprofit Arizona Public Health Association.