The following are currently required to report their emissions of greenhouse gases in Massachusetts:

• Facilities that are already required to obtain an "Air Operating Permit" from MassDEP (as established in 310 CMR 7.00, Appendix C), and that emit less than 5,000 tons/year of GHGs (on a CO2 equivalent basis, or "CO2e", which measures the "global warming potential" of gases compared with CO2) must report their "direct stack emissions" which include emissions from stacks, processes and vents, and fugitive emissions.
  
  
• "Appendix C Facilities" that emit more than 5,000 tons per year of GHGs on a CO2e basis must report all "direct emissions" (including those listed above) as well as emissions from motor vehicles.  "Appendix C Facilities" that have established "Restricted Emission Status" under 310 CMR 7.00 but emit more than 5,000 tons per year of CO2e GHG emissions are in this category.
  
  
• Facilities that are not covered by 310 CMR 7.00, Appendix C, but which emit more than 5000 tons per year of GHGs on a CO2e basis must report all "direct emissions" and emissions from stacks, processes, vents, and motor vehicles. 

These facility categories include:

• Electric generating units
  
  
• Emergency generators
  
  
• Industrial, commercial & institutional boilers 
  
  
• Wastewater treatment plants
  
  
• Municipal waste combustor
  
  
• Landfills
  
  
• Manufacturers
  
  
• Facilities using gases with "high global warming potential" gases, including methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) & sulfur hexafluoride (SF6)
  
  
• Facilities using combined heat & power
  
  
• Facilities burning biomass

Examples of fuel usage that would emit approximately 5,000 tons of greenhouse gases per year include:

• Combustion of 83,100,000 cubic feet of natural gas
  
  
• Combustion of 442,000 gallons of No. 2 fuel oil
  
  
• Operation of a 30 percent efficient natural gas-fired 1.0 megawatt electric generator running at 85 percent capacity