13.1 Sector Descriptions and Overview
This section includes discussion of all nonpoint sources in three EIS sectors: Bulk Gasoline Terminals, Gas Stations, and Industrial Processes – Storage and Transfer. Many of the sources reported to the point inventory as well; therefore, the EPA nonpoint survey is useful to avoid double-counting S/L/T-reported point emissions with EPA-estimated nonpoint emissions.
This section is broken into two categories: those sources related to stage 1 gasoline distribution and those related to aviation gasoline.
13.1.1 Stage 1 gasoline distribution
Stage 1 gasoline distribution is covered by the NEI in both the point and nonpoint data categories. In general terms, Stage 1 gasoline distribution is the emissions associated with gasoline handling excluding emissions from refueling activities. Stage I gasoline distribution includes the following gasoline emission points: 1) bulk terminals; 2) pipeline facilities; 3) bulk plants; 4) tank trucks; and 5) unloading at service stations. Emissions from Stage I gasoline distribution occur as gasoline vapors are released into the atmosphere. These Stage I processes are subject to EPA’s maximum available control technology (MACT) standards for gasoline distribution [ref 1].
Emissions from gasoline distribution at bulk terminals and bulk plants take place when gasoline is loaded into a storage tank or tank truck, from working losses (for fixed roof tanks), and from working losses and roof seals (for floating roof tanks). Working losses consist of both breathing and emptying losses. Breathing losses are the expulsion of vapor from a tank vapor space that has expanded or contracted because of daily changes in temperature and barometric pressure; these emissions occur in the absence of any liquid level change in the tank. Emptying losses occur when the air that is drawn into the tank during liquid removal saturates with hydrocarbon vapor and expands, thus exceeding the fixed capacity of the vapor space and overflowing through the pressure vacuum valve [ref 2].
Emissions from tank trucks in transit occur when gasoline vapor evaporates from (1) loaded tank trucks during transportation of gasoline from bulk terminals/plants to service stations, and (2) empty tank trucks returning from service stations to bulk terminals/plants [ref 3]. Pipeline emissions result from the valves and pumps found at pipeline pumping stations and from the valves, pumps, and storage tanks at pipeline breakout stations. Stage I gasoline distribution emissions also occur when gasoline vapors are displaced from storage tanks during unloading of gasoline from tank trucks at service stations (Gasoline Service Station Unloading) and from gasoline vapors evaporating from service station storage tanks and from the lines going to the pumps (Underground Storage Tank Breathing and Emptying).
Table 13.1 shows all non-Aviation Gasoline SCCs in the nonpoint data category for EIS sectors Bulk Gasoline Terminals, Gas Stations, and Industrial Processes – Storage and Transfer. For Stage 1 Gasoline Distribution, the nonpoint SCCs covered by the EPA estimates are also noted. The SCC level 2, 3 and 4 SCC descriptions are also provided. The SCC level 1 description is “Storage and Transport” for all SCCs.
| SCC | Description | Sector |
|---|---|---|
| 2501059120 | Petroleum and Petroleum Product Storage; Bulk Plants/Terminals: All Evaporative Losses | Bulk Gasoline Terminals |
| 2501060051 | Petroleum and Petroleum Product Storage; Gasoline Service Stations; Stage 1: Submerged Filling | Gas Stations |
| 2501060052 | Petroleum and Petroleum Product Storage; Gasoline Service Stations; Stage 1: Splash Filling | Gas Stations |
| 2501060053 | Petroleum and Petroleum Product Storage; Gasoline Service Stations; Stage 1: Balanced Submerged Filling | Gas Stations |
| 2501060201 | Petroleum and Petroleum Product Storage; Gasoline Service Stations; Underground Tank: Breathing and Emptying | Gas Stations |
| 2501070053 | Petroleum and Petroleum Product Storage; Diesel Service Stations; Stage 1: Balanced Submerged Filling | Gas Stations |
| 2501995120 | Petroleum and Petroleum Product Storage; All Storage Types: Working Loss; Gasoline | Industrial Processes - Storage and Transfer |
| 2505010000 | Petroleum and Petroleum Product Transport; Rail Tank Car; Total: All Products | Industrial Processes - Storage and Transfer |
| 2505020000 | Petroleum and Petroleum Product Transport; Marine Vessel; Total: All Products | Industrial Processes - Storage and Transfer |
| 2505020030 | Petroleum and Petroleum Product Transport; Marine Vessel; Crude Oil | Industrial Processes - Storage and Transfer |
| 2505020060 | Petroleum and Petroleum Product Transport; Marine Vessel; Residual Oil | Industrial Processes - Storage and Transfer |
| 2505020090 | Petroleum and Petroleum Product Transport; Marine Vessel; Distillate Oil | Industrial Processes - Storage and Transfer |
| 2505020120 | Petroleum and Petroleum Product Transport; Marine Vessel; Gasoline | Industrial Processes - Storage and Transfer |
| 2505020150 | Petroleum and Petroleum Product Transport; Marine Vessel; Jet Naphtha | Industrial Processes - Storage and Transfer |
| 2505020180 | Petroleum and Petroleum Product Transport; Marine Vessel; Kerosene | Industrial Processes - Storage and Transfer |
| 2505030120 | Petroleum and Petroleum Product Transport; Truck; Gasoline | Industrial Processes - Storage and Transfer |
| 2505040120 | Petroleum and Petroleum Product Transport; Pipeline; Gasoline | Industrial Processes - Storage and Transfer |
| 2510000000 | Organic Chemical Storage; All Storage Types: Breathing Loss; Total: All Products | Industrial Processes - Storage and Transfer |
| 2520010000 | Inorganic Chemical Storage; Commercial/Industrial: Breathing Loss; Total: All Products | Industrial Processes - Storage and Transfer |
13.1.2 Aviation gasoline distribution, stage 1 and 2
Aviation gasoline (also called “AvGas”) is the only aviation fuel that contains lead as a knock-out component for small reciprocating, piston-engine crafts in civil aviation [ref 4]. Commercial and military aviation rarely use this fuel. AvGas is shipped to airports and is filled into bulk terminals, and then into tanker trucks. These processes fall under the definition of stage 1, displacement vapors during the transfer of gasoline from tank trucks to storage tanks, and vice versa. Stage 2 involves the transfer of fuel from the tanker trucks into general aviation aircraft.
Table 13.2 shows, for Aviation Gasoline, the nonpoint SCCs covered by the EPA estimates and by the S/L/T agencies that submitted data.
| SCC | Description | Sector |
|---|---|---|
| 2501080050 | Petroleum and Petroleum Product Storage; Airports: Aviation Gasoline; Stage 1: Total | Gas Stations |
| 2501080100 | Petroleum and Petroleum Product Storage; Airports: Aviation Gasoline; Stage 2: Total | Gas Stations |
| 2501080201 | Petroleum and Petroleum Product Storage; Airports: Aviation Gasoline; Underground Tank: Breathing and Emptying | Gas Stations |