Part 253: DEC Finalizes Program for Climate Pollution Sources Tracking

On December 1, 2025, the New York State Department of Environmental Conservation (DEC) issued its final ruling for Part 253 (Mandatory Greenhouse Gas Reporting), which enacts the state’s new greenhouse gas (GHG) reporting program. These regulations were established to collect GHG emissions data from the state’s largest polluters, especially those located in disadvantaged communities.

Walden’s previous blog describing the draft Part 253 regulations introduced the proposed features of the program. Based on the information reported under this now-final program, DEC will generate an annual GHG Emissions Report in accordance with the agency’s mission to make air pollution information accessible to all.

What Is the Purpose of Mandatory GHG Reporting?

It should be noted that the Mandatory GHG Reporting Program relates only to the collection and reporting of data. Its purpose is not to impose requirements on facilities to lower GHG pollution or to be approved for emission allowances.

Beginning in June 2027, facilities that are subject to the Mandatory GHG Reporting ruling will be required to submit their GHG emissions data from the previous calendar year (2026). Most of these facilities most likely already report emissions data under existing state and federal emissions requirements.

The DEC is committed to continuing to provide the public with important emissions information, even with the United States Environmental Protection Agency’s recent modifications to federal air quality and GHG regulations. The DEC, together with the New York State Energy Research and Development Authority (NYSERDA), is advancing its goal of helping communities to understand the importance of lowering emissions and improving energy efficiency.

Does Part 253 Mandatory Greenhouse Gas Reporting Apply to My Facility?

Annual reporting will be required for the following emissions sources as listed in Part 253:

• Owners and operators of facilities in New York that emit 10,000 metric tons (MT) or more of carbon dioxide equivalent (CO₂e) per emissions year. These include electricity generation facilities, stationary combustion facilities, landfills, waste-to-energy facilities, natural gas compressor stations, and other infrastructure;
• Fuel suppliers that provide a quantity of fuel to an end user in New York that generates any amount of GHG emissions per emissions year. This includes suppliers of natural gas, liquid fuels, and petroleum products, liquefied natural gas and compressed natural gas, and coal;
• Waste haulers and transporters (exporters) for which the estimated emissions from solid wastes transported to landfills or combustion facilities outside of New York exceed 10,000 MT CO₂e emissions in any year;
• Electric power entities that emit any GHGs or that import megawatt hours (Mwh) into New York;
• Suppliers of agricultural lime and fertilizer that provide quantities necessary to generate any GHG emissions per emissions year; or
• Facilities that utilize systems for anaerobic digestion and liquid storage of waste, such as wastewater treatment plants and concentrated animal feeding operations, where wastes are imported to the facility or generated at the facility in amounts that would generate 10,000 or more metric tons of CO₂e per year.

More information and documents related to the GHG reporting requirements can be found on DEC’s website at the links below:

• Air Pollution Regulatory Revisions, https://dec.ny.gov/regulatory/regulations/proposed-emergency-recently-adopted-regulations/air-pollution-regulatory-revisions
• Mandatory Greenhouse Gas Reporting, https://dec.ny.gov/environmental-protection/air-quality/mandatory-greenhouse-gas-reporting
• Statewide Greenhouse Gas Emissions Report, https://dec.ny.gov/environmental-protection/climate-change/greenhouse-gas-emissions-report

If you need more assistance understanding the Part 253 requirements and completing all necessary reporting, Walden’s air experts can guide your facility through preparing emissions data for the upcoming year. Contact us today at 516-559-6976 for assistance.