Two Kansas men have pleaded guilty in federal court to operating a synthetic drug business that generated at least $16 million in sales in less than two years.

U.S. Attorney Barry Grissom says 58-year-old Tracy Picanso and 56-year-old Roy Ehrett, both of Olathe, each pleaded guilty Monday to one count each of conspiracy, producing and selling misbranded drugs, producing and selling counterfeit drugs and conspiracy to launder money.

Prosecutors say the men owned an Olathe-based business that produced and sold synthetic marijuana and stimulants in Kansas, Missouri, California, Texas, Georgia and Colorado.

Prosecutors say some of the drugs were manufactured in buckets with drill-powered mixers and tried out on “testers” who helped tweak the recipes by reporting on the drugs’ effects.

Sentencing is set for April 13.