(Not this kind of meth house.AMC)

The Drug Enforcement Agency (DEA) is taking aim at Colorado's marijuana industry.

In a June report — titled "Residential Marijuana Grows in Colorado: The New Meth Houses?" the DEA criticized the proliferation of large-scale marijuana grow operations in residential neighborhoods.

These growers are taking advantage of a loophole in Colorado state law, according to the report.

Colorado state law limits adult home-growers over the age of 21 to six plants per house. But a specific loophole in the law allows prospective growers to circumvent this rule.

Amendment 64, the law allowing people to grow and consume marijuana in their homes, also allows any adult in Colorado to "assist" any other adult in "possessing, growing, processing, or transporting" marijuana. Another provision, Amendment 20, allows caregivers — who grow marijuana for medical purposes — the ability to grow up to 99 plants for their patients.

These loopholes have given growers the ability to turn residential homes into massive grow operations, according to the DEA. Because Colorado's Marijuana Enforcement Division — the body created to regulate marijuana growers — can only regulate licensed grow operations and the unlicensed grow houses fall under the aforementioned amendments, the residential grow operations are in a legal gray area.

"Much like the 'meth houses' of the 1990s," reads the report. "Many of these homes may ultimately be rendered uninhabitable."

(Master Grower Ryan Douglas waters marijuana plant clones at Tweed Marijuana Inc. in Smith's Falls, Ontario, February 20, 2014.Reuters/Blair Gable)

Residential grow operations can render houses uninhabitable as growers often modify the electrical systems to install high-powered grow lights and air-conditioning units. Further, the modifications some growers make to the houses — including cutting holes in the floor and exterior walls to for ventilation tubes — can leave the houses structurally unstable, according to the report.

As well, local police departments have fielded numerous calls about these residential grow operations, including complaints about, "strong odors, excessive noise from industrial air-conditioning units, blown electrical transformers, and heavy vehicle traffic," according to the report.

The DEA also contends that this unlicensed marijuana is frequently shipped over state borders, and that the system is "extensively exploited by traffickers who operate large grows to supply out-of-state markets," where the marijuana may fetch higher prices.

But the DEA report doesn't quantify how much marijuana is actually shipped across state borders, notes The Washington Post's Christopher Ingraham.