Illegal drug traders have targeted Colorado as a base from which to traffic millions of dollars worth of weed.

With Colorado’s legal marijuana marketplace providing a safe haven for the illicit drug trade, local cartels are growing several varieties of cannabis, and covertly transporting it to other places in the U.S. where they earn millions of dollars in unlawful pot sales, the Big Story reported.

According to police authorities, one skydiving business owner carried hundreds of pounds of Colorado-grown weed in his planes en route to Minnesota where it was sold for millions of dollars.

Another Denver man has been arrested after sending over a hundred marijuana-filled FedEx packages to New York, where Buffalo drug dealers divided up the shipments for distribution, Fox 2 said.

Authorities have also charged 20 other drug traffickers, mostly coming from Cuba, who have relocated to Colorado to farm marijuana. The product is then sent to Florida, where weed remains illegal and fetches twice the price.

The recent cases confirm the longstanding arguments of legalized marijuana opponents who feared the state’s legal pot experiment would attract illicit drug traders into using Colorado’s marijuana haven to distribute the drug to states where it remains prohibited, ABC News wrote.

While one source of concern comes from tourists who buy weed legally in Colorado and bring it with them out of state, a bigger apprehension involves larger-scale traffickers who have taken advantage of Colorado’s legal pot trade to ship the drug to other more profitable markets.

Law enforcement authorities have admitted there is as yet no way to determine how much marijuana actually leaves Colorado. Illegal shipments seized from drug traffickers are not indicative over where the plants were actually grown.

Based on interviews with police officials as well as information taken from court documents, drug traffickers have already established several well-organized trade routes from Colorado’s booming pot industry.