Cannabis businesses

The legalization of recreational cannabis in Minnesota in 2023 presents a unique opportunity to promote environmental compliance and sustainability within the industry. It is important for cannabis growers and processors to determine various environmental regulations and permits that may apply to their businesses.

Air emissions

Cannabis cultivation and processing can impact air quality through emissions of volatile organic compounds. Volatile organic compound emissions include terpenes and solvents like propane and butane used in processing concentrates. The cultivation and harvest of cannabis and the operation of fuel-fired boilers, furnaces, generators, and other equipment can also release air pollutants, including nitrogen oxides. Air quality impacts can be minimized by controlling volatile organic compound emissions and implementing strategies to reduce odor.

State permits

Whether you need an air permit will depend on your various processes and potential to create air emissions. An air permit should be obtained prior to beginning construction and is needed if potential air emissions exceed certain thresholds or if a facility is required to follow a federal New Source Performance Standard.

Calculate emissions from all activities occurring at the business. The very smallest facilities may qualify as insignificant facilities, which do not need a permit. Some process-focused calculators can help you to determine the facility's potential and actual emissions. Potential emissions help identify if a facility needs a permit. Actual emissions will help identify the type of air permit you can qualify for by staying below permit limits.

• Boilers, furnaces, and space heaters air emissions calculator (p-sbap5-21)
• Internal combustion engines air emissions calculator (p-sbap5-25)
• Comparison of air permit flexibility options (aq2-29)

Federal permits

Two types of federal rules, the National Emission Standards for Hazardous Air Pollutants and the New Source Performance Standards, can apply to cannabis businesses and activities. National Emission Standards for Hazardous Air Pollutants can apply regardless of whether a facility needs an air permit. New Source Performance Standards can impact whether a facility needs an air permit.

Stationary engines or generators used for emergency backup power, routine power generation, or even to help level out demand on the electrical grid may be subject to federal air quality regulations depending on size and how the engine is being used. 

Air permit fees and due dates

Noise and odor

The MPCA is only involved in regulating noise or odor in some cases. Local governments typically address complaints about these issues. The MPCA is currently developing a new odor regulation.

Waste management

A waste is any material that can no longer be used for its original intended purpose. The cannabis industry generates various waste streams, some of which may be subject to specific regulations for solid waste and hazardous waste. Understanding these regulations is crucial for responsible waste management and avoiding potential compliance issues.

Cannabis waste disposal might have additional regulations due to its controlled substance status.

• See Minn. Stat § 4770.1200 for existing regulations on disposal of cannabis products.
• While the MPCA can advise on Minnesota regulations for cannabis waste management, the U.S. Drug Enforcement Administration has its own set of requirements.

Hazardous waste

While cannabis itself isn't typically considered hazardous waste, its cultivation and processing can generate materials that pose threats to human health and the environment if not handled properly. The hazardous waste identification and management page contains information on managing specific types of hazardous waste including pesticides, cleaning solvents, vape pen batteries, and pharmaceutical waste.

• Pharmaceuticals — management changes (w-hw3-33)
• Vaping liquids, e-cigarettes and nicotine wastes (w-hw4-65)
• Universal wastes (w-hw4-62)

You need a hazardous waste identification number if your business produces any amount of hazardous waste.

• Step 3: Obtain a hazardous waste identification number (w-hw1-03)

Businesses generating most types of hazardous waste are required to report annually, pay a fee, and obtain a license for the subsequent year. Facilities in Anoka, Carver, Dakota, Hennepin, Ramsey, Scott, or Washington County are licensed and inspected by their county. Facilities in Greater Minnesota are licensed and inspected by the MPCA. Facilities that produce only small amounts of hazardous waste can qualify as a very small quantity generator:

• VSQG collection programs: Instructions and list of available programs (w-hw2-51)

Hazardous waste fees and due dates

Solid waste

Most cannabis waste, including trimmings, packaging materials, and used soil, can be considered solid waste and follows standard regulations. Composting is the preferred method for plant material, and reuse is recommended for cannabis soil. Any paper waste or designated plastics should be recycled. Visit the MPCA waste and recycling page for details.

Wastewater

Wastewater from cannabis cultivation and manufacturing can contain pollutants such as cannabinoids including Tetrahydrocannabinol (THC), solvents, cleaners, pesticides, nutrients from fertilizers, residuals from plant and soil amendments, and reject water from water treatment systems. While there are no state-specific regulations that focus on cannabis wastewater, general environmental regulations apply.

Please note, irrigation associated with outdoor cultivation operations may be regulated by the Minnesota Department of Agriculture (MDA), the MPCA, or both depending on the operational activities. In general, if irrigation is not collected like other outdoor agricultural crop operations, it may be allowed to infiltrate. Outdoor cultivators should contact both the MDA and the MPCA to determine the requirements based on their proposed operations. Indoor cultivators are expected to manage their irrigation discharges according to the options below.

In sewered areas, wastewater typically is discharged to the sanitary sewer for treatment and disposal at a wastewater treatment plant (WWTP). Check with your city to confirm whether they have the capacity and ability to manage your wastewater. The MPCA recommends you fully characterize your wastewater with analytical results and identify your maximum daily, monthly, and annual flow volumes to aid in discussions with your city.

In unsewered areas, cannabis wastewater management options include:

• Capture wastewater in a holding tank and haul it to a WWTP. Check with the WWTP to determine whether it will accept industrial wastewater.
• Capture wastewater in a holding tank/structure and land apply it as an industrial by-product (IBP) if the material is suitable for land application. This option also allows IBP to be transferred to an active liquid manure storage area. A State Disposal System (SDS) permit may be needed. Permit applications should be submitted at least 180 days in advance of the activity start date. More information about land application is found on the MPCA’s IBP program webpage; refer to the Wastewater permits page for information about permits.
• Capture and discharge wastewater into a subsurface disposal system similar to but separate from a septic system. This type of system is considered a Class V injection well; refer to EPA guidance.
• Spray irrigate wastewater with an SDS permit if the material is suitable for land application. Permit applications should be submitted at least 180 days in advance of the activity start date. More information about industrial spray irrigation is found in MPCA’s guidance on industrial spray irrigation, as well as information on wastewater permits.
• Discharge to a surface water or a storm drain that empties into a surface water requires an individual National Pollutant Discharge Elimination System (NPDES)/State Disposal System (SDS) permit from the MPCA’s industrial wastewater program. This type of permit regulates a treatment and disposal system that discharges a specified amount of a pollutant into a surface water. 

If you are considering an option(s) for an unsewered area, contact the Industrial Wastewater Program to determine applicability, permitting requirements, and prohibitions.

Specific actions that are not allowed include directing cannabis wastewater to: 

• the ground surface through an open drain or pipe
• the saturated zone

Septic systems are not suitable for the industrial portion of the waste stream

Minnesota subsurface sewage treatment systems (SSTS) Rules are very clear and specific in their scope: SSTS regulations apply specifically to sewage. “Sewage,” as defined in Minn. R. 7080.1100, subp. 73, includes waste from toilets, bathing, laundry, culinary operations, and associated floor drains, along with typical domestic use of cleaners and medications. The rules do not regulate non-sewage waste streams, such as industrial by-products from manufacturing operations, including those from cannabis cultivation and processing.

Per Minn. R. 7080.1050, systems that receive both sewage and non-sewage must follow SSTS requirements for the sewage portion, and any additional regulatory requirements for the non-sewage portion of the waste. This can be both cost prohibitive and problematic for system functionality given what SSTS are designed to accomplish and the complexities posed by non-sewage waste streams.

Separate waste streams

To align with SSTS rule framework and ensure both long-term system function and protection of Minnesota’s environment and public health, the MPCA guidance is to separate sewage and non-sewage waste streams at cannabis facilities. This separation allows for:

• the sewage portion (e.g., employee bathrooms, breakroom kitchens, laundry) to be managed under existing SSTS rules through the local permitting process
• the non-sewage waste (e.g., nutrient-laden hydroponic flushes, concentrated plant waste liquids, cleaning solutions from processing equipment, reverse-osmosis discharge) to be addressed through industrial wastewater permitting pathways dependent on each unique facility

Cannabis processing wastewater often contains high-strength ingredients, altered pH levels, excess nutrients, or industrial additives that go beyond the treatment capabilities and regulatory allowances of an SSTS. Discharging such waste into a septic system can be damaging, cause premature failure, and potentially contaminate groundwater.

Industrial stormwater

Any facility that has material, equipment, or activities exposed to rain, snow, or runoff should apply for an Industrial stormwater permit. Businesses that don’t have any materials, equipment, or activities exposed to the elements may qualify for the no-cost no-exposure certification and avoid the permit and fees. If you have only a few materials outside, consider moving them inside to qualify for no-exposure certification. 

The need for an industrial stormwater permit depends on the business’s revenue-generating activities, expressed as narrative activities or SIC/NAICS codes.

• Step 1: Do you need a permit?

While the cannabis industry is not specifically listed, some activities such as chemical manufacturing of medicinals and botanicals or food processing of essential oils and fats could apply to cannabis businesses.

Industrial stormwater general permit fees and due dates

Water withdrawal

In Minnesota, a water-use permit is required from the Minnesota Department of Natural Resources (DNR) if a business withdraws more than 10,000 gallons of water per day or 1 million gallons per year for any non-domestic purpose. When reviewing applications, the DNR considers factors such as water source, withdrawal volume, potential resource impact, and the business’s conservation measures.

• Water appropriation permit program (DNR)

Water withdrawal permit fees and due dates

Storage tanks

Minnesota regulates storage tanks used for petroleum or hazardous liquids. Aboveground tanks larger than 500 gallons and underground tanks larger than 110 gallons need to be registered with the MPCA.

Storage tanks permit fees and due dates

Beyond compliance

Cannabis businesses can operate successfully while minimizing their environmental impact. Here are some key practices to consider:

• Minimize hazardous waste: Identify areas where generating hazardous waste can be reduced. Follow regulations and dispose of waste properly to protect employees and the environment.
• Reduce and reuse: Choose eco-friendly packaging that uses minimal materials. Consider take-back and reuse programs for added sustainability.
• Plan ahead: Purchase only the pesticides and chemicals you need to avoid waste due to regulation changes.
• Minimize odors and volatile organic compound emissions: Implement odor control technologies like carbon filtration to reduce unwanted scents during cultivation.
• Maintain your system: Regularly inspect and service your solvent extraction equipment to prevent solvent leaks.
• Capture and reuse water: Indoor facilities can use water storage and recapture methods to reduce overall water use.
• Keep it clean: Prevent pollution by never dumping anything down storm drains, maintaining a clean property, and using dry absorbents for spills.
• Educate yourself: Stay informed of evolving regulations to ensure compliance.
• Get help: Partner with MPCA environmental experts for guidance on sustainable practices specific to your business.

By following these tips, your cannabis businesses can operate responsibly and contribute to a greener future.