Environmental Impacts of the Marijuana Industry

April 17, 2019

Plants growing inside a marijuana facility

You're probably wondering why the Michigan Department of Environmental Quality (MDEQ) is writing an article about the marijuana industry. After all, isn't the marijuana industry just growing plants? What many don't realize is that although marijuana is often thought of as a "green" industry, the growing and processing of marijuana at an industrial scale presents many environmental risks.

Marijuana is commonly grown indoors where environmental factors, such as light, water, and nutrient inputs are carefully controlled. Fertilizers, herbicides, and pesticides used by growers threaten water, land, and air quality if not properly applied and disposed of. In addition, growing marijuana plants can require substantial amounts of water, which can lead to large and sometimes illegal withdrawals of groundwater or surface water.

Flow process of the marijuana industryProcessing the plant into marijuana infused products also has environmental impacts. Facilities doing the processing use solvents such as butane, propane, hexane, alcohol, benzene, and supercritical carbon dioxide to extract essential oils. Many of these solvents are volatile organic compounds (VOCs), which contribute to the formation of ground-level ozone. Emissions of VOCs are of concern in Michigan as there are currently areas not meeting the national health-based ozone standards. Additional emissions of VOCs from this emerging industry may increase ozone formation and exacerbate existing air quality issues.

Solvents used in processing operations may pose a threat to public health, the environment, and wildlife if they contaminate our water resources. Solvents should not be discharged directly into surface water or storm drains. Ideally, wastewater from processing facilities will be pre-treated before being sent to the local wastewater treatment plant. In addition, any solid wastes containing solvents may be considered hazardous waste and must be disposed of accordingly. Even non-hazardous marijuana waste has specific waste handling restrictions.

Another concern related to the marijuana industry are nuisance odors. Odors may originate from the plants themselves or from activities done during growing and processing. Odors are best controlled by installing an activated carbon filter at the facility and implementing an odor control plan. In addition, all odor complaints, whether from industrial or residential sources, will be handled by local governments.

So, what is MDEQ doing to prevent negative impacts to the environment from the marijuana industry? Many existing environmental regulations apply to the marijuana industry. Existing regulations include permitting programs for water withdrawals and air emissions, regulations related to the disposal of plant wastes and hazardous materials, as well as regulations covering how to properly handle wastewater from these processes. The MDEQ is working to ensure the marijuana industry is aware of existing regulations and that facilities are handled consistently across the state.

It is important to note that the MDEQ only regulates industrial marijuana operations and any environmental impacts related to residential grows, processing, or use are handled by local authorities.

The Michigan Department of Licensing and Regulatory Affairs Bureau of Marijuana Regulation has a clearinghouse of information on this industry, not limited to environmental regulations and impacts. Any questions on which environmental regulations may apply to you or about overall impacts of the marijuana industry may be directed to the MDEQ Environmental Assistance Center at 1-800-662-9278.


# # #

Take a short survey and let us know what you think about MI Environment.