6.12 Portable Fuel Container Spillage

Category 1434

6.12.1 Introduction

Category 1434 covers organic emissions (TOG and ROG) from portable fuel container spillage. Portable fuel containers, or “gas cans” and gas can spouts, are used to refuel off-road engines and equipment (i.e. lawnmowers, chainsaws, motorcycles, etc.). Portable fuel containers are made of either plastic or metal and come in a variety shapes and sizes ranging from one to more than six gallons in capacity. Portable fuel containers are designed for transportation, storing and dispensing fuel. The California Air Resource Board (CARB) started regulating all portable fuel containers manufactured for sale and use since 2000. The regulations are intended to reduce refueling emissions from equipment and engines in the off-road categories that are predominantly refueled with portable fuel containers. The Mobile Source Control Division (MSCD) of CARB conducted surveys to establish the number of statewide portable fuel container population in 1998. These surveys show that there are 9,878,706 portable fuel container units statewide. The data also indicate that 94% of portable fuel containers are used in residential households, and 6% for commercial use. Therefore, the effect of the statewide regulations on commercial users (i.e., tree trimming services, landscape maintenance professionals, automobile tow services, etc.) would be insignificant. Using total container population and an average useful life of 5 years suggested by several manufacturers, ARB estimates the total sales of all portable fuel containers statewide.

6.12.2 Methodology

This category accounts for evaporative emissions resulting in spillage from refueling, transport and storage of the portable fuel containers. These portable containers contribute emissions by:

• permeation of vapors through walls in containers made from plastic,
• escaping fumes while fuel is being poured into equipment,
• spillage and/or over-filling as fuel is being poured into equipment,
• spillage and evaporation through secondary vent holes, and
• evaporation through inadequately capped spouts.

The evaporative emissions are derived by California Air Resources Board (CARB) inventory staff. This significant emissions dataset, sorted by county, is published every few years and is a product of the State Implementation Plan (SIP) emissions document formally known as the California Emissions Projection Analysis Model (CEPAM) inventory ¹⁹⁹. BAAQMD staff export the emissions data directly from CEPAM into the District’s Base Year inventory package. This calculation approach and collection of categories are internally termed as “CARB Source Categories”. The current base year inventory uses the 2016 CEPAMv1.05 to estimate emissions from “CARB Source Categories”. This version of the CEPAM derives emissions from a 2012 base year inventory and contains backcasts and forecasts from year-2000 to year-2035. All applicable regulatory and technological controls are assumed to be built into the CEPAM dataset during CARB staff’s inventory computation work. After the emissions data are exported, the inventory for CARB Source categories is taken through a quality assurance (QA) process.

6.12.3 Changes in Methodology

This base year inventory emissions data were obtained from the CARB’s 2016 CEPAMv1.05. In comparison, the BY2011 methodology involved area source categories developed by District Emission Inventory staff.

6.12.4 Emissions

A summary of emissions by category, county, and year are available via the associated data dashboard for this inventory publication.

6.12.5 Trends

(a) Historical Emissions/History

The CARB Mobile Source Control Division (MSCD) survey indicated that 1,975,741 units of residential and commercial portable fuel container were sold in 1998. It was assumed 20 percent of these units are sold in the Bay Area. This figure was derived from Bay Area household population compared to statewide data. CARB has grouped the various sizes of portable fuel containers into three categories: 1 - 1.5 gallons, 2 - 2.5 gallons, and 5 – 6 gallons).

Three different methods are used for backcasting to project historical emissions prior to year-2000 going back to year-1990, which is the starting year of the current base year inventory (referred to as BY2015). Following preliminary evaluation of the data available for initial years (post-year 2000) in the CEPAM inventory, BAAQMD staff recommends a backcasting approach. The default backcasting approach is defined by a formula here –

\[ \begin{eqnarray} \text{BY2015 emissions for year X for county Y} = \text{BY2011 total emissions for year X} \\ \\ \times \dfrac{\text{BY2015 year-2000 emissions}}{\text{ BY2011 year-2000 emissions}} \\ \\ \times \dfrac{\text{county Y fraction}}{\text{ fractional total}} \end{eqnarray} \]

This calculation is referred to as the BY2011 scaling method (based on the previous base year inventory). The second calculation approach is to derive the linear regression best fit of the year 2000-2008 CARB Sources emissions data for a category, species, and county, and extrapolate that data back in time. If this backcasting results in negative emissions prior to a certain year, the lowest positive emission value is held constant from that particular year back to year-1990. The third possible calculation approach is to use a specific growth profile for the category, provided by the in-house staff expert. These custom growth profiles are often derived from surrogate data provided by another agency or resource, or available activity data that is assumed to scale with the emissions for that specific CARB Source category.

For portable fuel container spillage, the BY2011 scaling method is used to derive emissions for years 1990 through 1999.

(b) Future Projections/ Growth

CARB projected TOG/ROG emissions from portable fuel containers are based on the CARB’s 2016 CEPAM v1.05 emission inventory. Emissions forecasting was done by holding the year-2035 emissions data constant through and up to year-2040. For CARB Sources, emissions are forecasted by CARB staff by applying growth profiles to the base year-2012 inventory data.

(c) Controls

On September 11, 2000, CARB regulated all portable fuel containers manufactured for sale and use in California. This regulation required all portable containers and spouts to have an automatic shut-off feature to prevent overfilling of power equipment fuel tanks. The spouts should also have an automatic closing feature so the portable fuel container would be sealed when not in use. This gas can regulation prevented spills during equipment fueling and evaporation during fuel storage. CARB estimated an overall reduction of 3 tons per day (approximately 30 percent compared to previous estimates) in ROG emissions if this regulation was fully implemented by 2005. California Air Resources Board (CARB) adopted amendments to the portable fuel container (PFC) regulation on April 1, 2017²⁰⁰. The amendments required all new PFC products to conduct certification testing using the updated Certification Procedure (CP) 501 and all existing PFC products to recertify to the updated CP-501 by July 1, 2018.

6.12.6 Uncertainties

The estimated units of residential and commercial portable fuel containers for Solano and Sonoma counties under District’s jurisdiction may contribute to an increased uncertainty of the Bay Area Portable Fuel Container Spillage emissions.

6.12.7 Contact

Author: Michael Nguyen

Reviewer: Ariana Husain

Last Update: November 06, 2023

6.12.8 References & Footnotes

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199. CARB. Criteria Pollutant Emission Inventory Information (CEPAM) . [accessed 2023 Mar 13]. https://ww2.arb.ca.gov/criteria-pollutant-emission-inventory-data↩︎

200. CARB. 2017. Portable Fuel Container Regulation Amendment Fact Sheet, https://ww2.arb.ca.gov/sites/default/files/2021-02/portablefuelcontainerregulationamendmentfactsheet.pdf↩︎