DAYTON, Ore. (AP) — Two large, unlicensed, unpermitted marijuana grows have been busted in a rural area of Yamhill County, southwest of Portland, Oregon, according to law enforcement officials.

The Yamhill County Sheriff’s Office said Tuesday that multiple complaints about two properties in Dayton led them to start investigating and serve search warrants.

One of the operations had 46 greenhouses, nearly 6,700 pot plants and over 10,000 pounds of drying or dried marijuana, officials said. Twelve people were arrested at the site ranging in age from 19 to 60. Most were arrested on suspicion of unlawful manufacture of marijuana and unlawful marijuana possession, officials said.

The second grow had 53 unpermitted greenhouses with more than 15,000 plants, according to sheriff’s officials.

Yamhill County Code Enforcement and inspectors went to the properties to address solid waste concern and electrical code violations, officials said.

Large camps were found at both locations where people who were growing and processing the marijuana were living. A considerable amount of solid waste and refuse was found in the camps, officials said.

Referrals also were made to the regional Oregon Watermaster about water diverted from Palmer Creek and from a pond on one property, officials said.

It took the Sheriff’s Office and people from over a dozen other agencies — including police departments, the Oregon Army National Guard and others — four days to complete the search warrants, officials said. The work involved dismantling and eradicating the grows and continuously maintaining security while that work happened.

Illegal marijuana grows have been a persistent problem throughout the West, especially in southern Oregon.