Class 1 consists of the operation, repair, maintenance, or minor alteration of existing public or private structures, facilities, mechanical equipment, or topographical features involving negligible or no expansion of use beyond that existing previously. The Class includes, but is not limited to: remedial, maintenance, conversion, and abandonment work on oil, gas, injection, and geothermal wells involving the alteration of well casing, such as perforating and casing repair, removal, or replacement; installation or removal of downhole production or injection equipment, cement plugs, bridge plugs, and packers set to isolate production or injection intervals.