The majority of States regulate spent aerosol cans as any other solid waste. If the spent can is not empty, it can be regulated as a hazardous waste. This is especially true if the propellant used is flammable, making the can an ignitable waste. Therefore, unless steps are taken to completely drain liquid and propellant from the can (such as a can puncture system) spent aerosols are typically collected and disposed of as hazardous waste. Some waste aerosols and gas cylinders may meet the strict definition of an empty container. To be classified as empty, they must meet these three criteria:
- Contain no compressed ignitable gas propellant or product (i.e. will not release pressure through an open, working valve or the propellant is not ignitable);
- All liquid product that can be dispensed through the valve has been (i.e. will not spray product through an open, working valve); and
- Less than 3% of the product capacity of the container remains.
A handful of States allow spent aerosol cans to be handled under State Universal Waste rules (email Caltha LLP if you would like to know if your State is included), although this waste stream is not a Federal universal waste under 40 CFR 273. The Minnesota Pollution Control Agency has finalized rules that will allow generators to manage aerosol cans as universal wastes.
Because documenting that an aerosol container or gas cylinder meets “RCRA Empty” standard can be impractical, MPCA allows generators to assume that an aerosol container is empty when both the following conditions are met:
- No liquid is felt or heard when the container is shaken by hand; and
- No gas or liquid is released when the spray/discharge valve is activated and the container rotated through all directions, as long as the valve is not observably or known to be clogged.
Hazardous waste aerosols and gas cylinders that are not empty can be managed under rules equivalent to universal wastes in Minnesota. Generators must accumulate hazardous waste aerosols and gas cylinders in closed containers labeled with one of these phrases:
- Universal Waste Aerosols/Gas Cylinders (whichever is appropriate)
- Waste Aerosols/Gas Cylinders
- Used Aerosols/Gas Cylinders
Accumulated hazardous waste aerosols/gas cylinders can be stored on-site for no more than one year and must be dated to verify how long they have been stored. Generators can ship hazardous waste aerosols/gas cylinders without a hazardous waste manifest to any site that has agreed to accept and properly manage them.
Hazardous waste aerosols and gas cylinders may no longer be punctured or vented in Minnesota after January 1, 2017, unless all hazardous waste propellant gases, product gases, and liquids are captured and properly disposed. Charcoal and activated carbon filters do not capture hazardous waste propellants or gases for proper disposal. The deliberate release of hazardous waste propellant or compressed gas to the atmosphere is prohibited by MPCA Hazardous Waste Rules, but for many years MPCA elected not to enforce this prohibition. Prior to 2017, this allowed generators and collection sites to puncture hazardous waste aerosols and release ignitable hazardous waste to the atmosphere.