Burns done for agricultural operations do not need any smoke or other air quality permit from the State. Air Regulation 9 defines agricultural burning as "the open burning of cover vegetation for the purpose of preparing the soil for crop production, weed control, maintenance of water conveyance structures related to agricultural operations, and other agricultural cultivation purposes."
"Agricultural operations" do not include burns for multiple objectives nor for forest or habitat management. Generally they apply to plant crops raised for sale, and to enhance forage for livestock.
Some counties in Colorado do require that agricultural open burns have County smoke permits. Contact your local county health department for more information. Check with the fire department about fire control permits as well.
Training Burns: Many prescribed fires provide training for individuals, firefighter classes, or fire departments.
Noncommercial Cooking, Instructional, or Recreational Fires: "Fires used for noncommercial cooking of food for human consumption, or for instructional, training or recreational purposes" do not need a smoke permit.
Noncommercial Burning of Private Household Trash: Regulation 9 states that noncommercial burning of trash is allowed in the unincorporated areas of counties of less than 25,000 population at the time of to the latest federal census, provided such open burning is subject to regulations of the Board of County Commissioners for such county as adopted by resolution. Such regulations may include smoke permit provisions and/or prohibit any burning that would result in the exceedance of any National Ambient Air Quality Standards.
Colorado Air Quality Control Commission Regulation 9 says that no air quality permit is needed for "noncommercial burning of private household trash in particulate matter (PM10) attainment areas unless local ordinances or rules prohibit such burning." Since all areas of Colorado are in attainment of PM10 standards, only local ordinances or rules would apply to private burning of household trash. Therefore, If you want to burn your own trash, check with the county to see whether any local permits or prohibitions apply.
Safety Flares used to signal danger to the public are exempt from smoke permits.
Animal Parts and Carcasses: The open burning of animal parts or carcasses is not included in the exemption for noncommercial trash burning. Contact the Colorado Department of Agriculture if you need to burn carcasses. In addition, Regulation 9 says that for carcass burns, "[a]ll necessary safeguards shall be utilized during such non-permitted open burning to minimize any public health or welfare impacts. In addition, the owner or operator shall take steps to ensure that all surrounding and potentially impacted residents, businesses, schools, and churches are notified prior to beginning the open burn."