Homes are not designed to be used as grow operations for any plants. The result of growing an excess amount of vegetation inside private homes is damage to the walls and other structures with the potential for unhealthy mold.

After the November elections, there are now eight states that allow for the legal recreational use of marijuana: Alaska, California, Colorado, Maine, Massachusetts, Nevada, Oregon and Washington. Seven of these states allow for the growing of recreational marijuana in private homes or on the property of private residences.

The one that does not, Washington probably understood the mold issue. Washington has to deal with excess moisture with several regions having some of the highest annual rainfall in the United States. California and Nevada have regions with the lowest rainfall in the United States.

Alaska, Nevada, Maine, Colorado and Massachusetts allow each adult to grow up to six plants with the maximum number for each residence being 12. Alaska, Colorado and Maine stipulated that only half of the plants can be mature flowering plants. Massachusetts and Nevada do not make such a stipulation, so all 12 plants can be adult mature plants. All but Alaska require the plants to be grown in an enclosure of some sort, undetectable to the general public.

The state of Maine defines an immature plant as a nonflowering retail marijuana plant that is taller than 24 inches and wider than 18 inches. A flowering plant is defined as one that has gone into the cycle to produce buds or flowers. So the space to grow 12 plants, allowing for a conservative two inches around, is over 35 square feet. This is the size of two average closets, a third of the average bedroom or taking up all the space of an average bathroom if the sinks and tub are also used.

Oregon made a better decision by allowing only four plants to be grown in any one household. That takes up only 12 square feet or only part of the average closet. Furthermore, the footprint of four plants fits into inexpensive fully contained grow rooms suitable for use indoors.

A grow system for 12 plants runs into the thousands. It is obvious that many adults — especially if they do not own the home they live in — are not going to bother with a system that would prevent damage to room the marijuana is to grow in.

With 12 plants, there will be problems. The state of Colorado has already experienced considerable problems with damage to structures and serious health concerns due to mold. Indoor marijuana grow homes are the perfect environment for dangerous mold.

This problem has caught law enforcement and first responders unaware. While most would think of large grow farms as being the greatest risk, the materials in a conventional home — fiber board walls and carpeting — create an excellent environment for mold.

First responders in Colorado are encountering extremely high levels of mold, and this is a threat to those who breathe the mold. Jim Gerhardt with the Colorado Drug Investigators Association reported that one officer was hospitalized for months due to mold exposure in a marijuana grow house.

While formal studies have been done on illegal grow homes, the same concern will arise for many legal home growing with the ability to grow 12 large plants.

Dr. John Martyny with National Jewish Health led a study that investigated toxic mold in marijuana grows in cooperation with Denver law enforcement. The study looked at 30 grow operations with some having as few as 11 plants.

"The combination of warm temperatures and high humidity found in many indoor marijuana grow operations can fuel extensive mold growth," Martyny said. "Airborne levels of mold spores that we found inside these structures may subject the occupants, emergency personnel and other individuals to significant health hazards, especially allergies, asthma, hypersensitivity pneumonitis and other respiratory diseases."

In order to assure health safety, it is critical to keep mold from forming on marijuana plants and from mold forming on the materials in the environment. To most, the mold on the actual marijuana plant may cause some respiratory distress and lung disease, but for the immunocompromised patient it can be quite problematic and even deadly.

Washington did it best by not allowing the growing of recreational marijuana in any private homes. Oregon sought to limit the number of plants to the number that might be safely contained in a controlled growing environment to prevent mold growth.

The remaining states have opened up the potential for serious threats to the health of those who live in the home, those who may reside in the home in the future and those first responders who are charged with protecting the home.