EPA Announces Leaded Fuel Endangerment Finding

January 13, 2022

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by Mark Phelps (AvWeb) In a long-anticipated move, the Environmental Protection Agency (EPA) announced today (Jan. 12) that it “will take the necessary steps to regulate lead pollution from aircrafts (sic).” Those steps start with proposing an “endangerment finding” on leaded aviation gasoline, expected by the end of this year. Finalizing that finding is expected in 2023.

The EPA announcement listed a rash of damning statistics, including the number of piston aircraft using leaded fuels (170,000) and the number of airports from which they operate (20,000). The EPA announcement projects that 70 percent of all lead introduced to the atmosphere comes from those aircraft, and that people who live close to airports (“over 5 million people, including more than 360,000 children under the age of five”) are most vulnerable.

For many years, the case for banning leaded aviation fuel has been a tug-of-war between the EPA and the FAA, which has resisted the ban based on safety factors involving the risk of detonation, specifically among high-performance engines. Swift Fuels has supplemental type certificates (STCs) available for its UL94 unleaded fuel for 33 Lycoming engine series (up to the AEIC-540-D) and for 24 Continental engine series (up to the TSIO-550-K). As for those higher-power engines not yet covered under the STC program, the company posts on its website, “Swift Fuels has been conducting extensive scientific research, fuel testing, engine testing, and flight testing on all viable high-octane alternatives to replace 100LL [low-lead] since 2012. Our number 1 candidate to fully replace 100LL is a premium 100-octane unleaded avgas product that is already patented and is currently undergoing testing and certification with the FAA.”

General Aviation Modifications Inc. (GAMI) co-founder George Braly asserted last summer that his company’s G100UL drop-in replacement for 100LL, which has STCs available for a growing number of engines, is expected to be approved for “literally several hundreds of additional makes and models of popular engines,” with “fleetwide expansion” of the list of approved aircraft models by the first or second quarter of this year. He estimates the retail cost of the STCs to be on par with those aircraft owners acquire to use automotive gasoline. READ MORE

Leaded Aviation Gasoline Exposure Risk at Reid-Hillview Airport in Santa Clara County, California (Mountain Data Group)

Eliminating Lead Emissions From Small Aircraft Will Require Concerted Efforts Across the Aviation Sector, Says New Report (National Academies of Sciences, Engineering, Medicine)

Options for Reducing Lead Emissions from Piston-Engine Aircraft (National Academies of Sciences, Engineering, Medicine)

County of Santa Clara and Partners Call for Stronger Collective Action Against Aircraft Lead Emissions (County of Santa Clara)

Report calls for multipronged action to mitigate small aircraft lead emissions -- Amy Pritchett, head of aerospace engineering, led the National Academies study (Penn State)

The EPA may finally reckon with aviation’s dirty secret -- "It’s unconscionable to think about the hundreds of thousands of children that have been exposed to lead over all of these years from airport activity." (Grist)

Leaded gas was phased out 25 years ago. Why are these planes still using toxic fuel? Piston-engine aircraft remain the single largest source of highly toxic airborne lead. (NBC News)

Excerpt from National Academies of Sciences, Engineering, Medicine: Significantly reducing lead emissions from gasoline-powered aircraft will require the leadership and strategic guidance of the Federal Aviation Administration (FAA) and a broad-based and sustained commitment by other government agencies and the nation’s pilots, airport managers, aviation fuel and service suppliers, and aircraft manufacturers, says a new congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine. While efforts are underway to develop an unleaded aviation fuel that can be used by the entire gasoline-powered fleet, the uncertainty of success means that other steps also should be taken to begin reducing lead emissions and exposures, the report says.

Small gasoline-powered aircraft are the single largest emitter of lead in the United States, as other major emission sources such as automobile gasoline have been addressed. A highly toxic substance that can result in an array of negative health effects in humans, lead is added to aviation gasoline to meet the performance and safety requirements of a sizable portion of the country’s gasoline-powered aircraft. When emitted from aircraft exhaust, lead can be inhaled by people living near and working at airports. Lead exposures also can occur from exhaust deposited on soil and other surfaces, spills and vapor emitted during refueling, and contact with residue left on aircraft engines and other components. Even at low exposures, as measured by blood lead levels, lead has been linked to effects such as decreased cognitive performance in children.

“Because there is no known safe level of lead in the blood, there is a compelling reason to reduce or eliminate lead emissions from small aircraft,” said Amy R. Pritchett, professor and head of the department of aerospace engineering at Pennsylvania State University and chair of the committee that wrote the report.

Gasoline-powered piston-engine aircraft perform critical societal functions, including medical airlifts, aerial firefighting, business transport, crop dusting, pilot training, and search and rescue. They are also commonly used for personal and recreational flying, and are critical for meeting transportation needs in rural and remote regions. About one-third of all gasoline-powered aircraft, which include some of the most heavily used small airplanes and helicopters, require leaded gasoline to provide needed octane levels. Due to the small market for aviation gasoline and limited fueling infrastructure at most of the country’s more than 13,000 airports, leaded aviation gasoline is usually the only fuel available to operators of small aircraft.

In order to reduce the environmental health risks caused by aviation lead, the FAA should coordinate efforts to reduce emissions and exposures in multiple ways, the report says. The FAA should work with other federal agencies, such as the U.S. Environmental Protection Agency and Occupational Safety and Health Administration, and organizations within the aviation community to initiate campaigns for education, training, and awareness of lead hazards and mitigation measures targeted to pilots, airport personnel, and aircraft technicians.

A concerted effort also is needed to motivate fuel refiners to reduce the amount of lead added to high-octane aviation gasoline, the report says. The FAA should explore policy options to achieve this, while prompting airports to add the fueling infrastructure needed to dispense more unleaded gasoline. The recertification requirements for aircraft that do not require high-octane fuel also should be eased, encouraging pilots to use lower octane unleaded fuel. The report further recommends that a goal and time frame be established, potentially with congressional direction, for all future aircraft that burn gasoline to be able to use unleaded fuel.

The report emphasizes that the elimination of lead from all aviation fuel should remain a public policy priority while these efforts to sustain progress in reducing aviation lead emissions and exposures continue. The FAA should continue to collaborate with the aviation industry and fuel suppliers in the search for a high-octane unleaded fuel that can be used by all gasoline-powered aircraft, the report stresses. The FAA also should collaborate with other government agencies such as NASA to promote the development, testing, and certification of emerging lead-free propulsion systems for small aircraft applications, including battery and hybrid electric systems.

The study — undertaken by the Committee on Lead Emissions From Piston-Powered General Aviation Aircraft — was sponsored by the U.S. Department of Transportation. The National Academies are private, nonprofit institutions that provide independent, objective analysis and advice to the nation to solve complex problems and inform public policy decisions related to science, technology, and medicine. They operate under an 1863 congressional charter to the National Academy of Sciences, signed by President Lincoln. READ MORE

Excerpt from Mountain Data Group: Executive Summary
Background
Lead (Pb) is a naturally occurring and ubiquitous metal, used in human industry since antiquity. Lead emissions persists in the lived environment. Lead ingested or inhaled resides in the human bloodstream for about sixty days, but can persist in human tissue, the brain, and the skeletal system for many decades after an exposure event. Lead has
no known biological purpose in the human body.

As noted by Bellinger and Bellinger (2006), because “lead serves no useful purpose in the body, exposure to it – regardless of route – can lead to toxic effects.” Children exposed to lead suffer substantial, long lasting, and possibly irreversible negative health, behavioral, and cognitive outcomes. Importantly, negative cognitive and behavioral effects in leadexposed children are higher at lower blood lead levels (BLLs), with deleterious effects observable at BLLs in the range of 2 to 3 µg/dL (Miranda et al., 2007, 2009). On the question of safe exposure, the Centers for Disease Control and Prevention (CDC) states: “No safe blood lead level in children has been identified. Even low levels of lead in blood
have been shown to affect IQ, ability to pay attention, and academic achievement.”

Over the last four decades, the BLLs of children in the United States have declined significantly, coincident with a series of policies that expelled lead from paint, plumbing, food cans and automotive gasoline. Most effective was the phase-out of tetraethyl lead (TEL) from automotive gasoline induced by provisions of the Clean Air Act (CAA) of 1970.

While TEL is no longer used as an additive in automotive gasoline, it remains a constituent in aviation gasoline used by an estimated 170,000 piston-engine aircraft (PEA) nationwide.

Consumption of lead-formulated aviation gasoline accounts for about half to two thirds of current lead emissions in the United States (Kessler, 2013). In a recently published consensus study on Options for Reducing Lead Emissions by Piston-Engine Aircraft by the National Academies of Sciences, Engineering, and Medicine, the authors note: “While
the elimination of lead pollution has been a U.S. public policy goal for decades, the GA [General Aviation] sector continues to be a major source of lead emissions.” (2021, pg. 10-11).

Several studies have linked aviation gasoline use to elevated atmospheric lead levels in the vicinity of airports. The U.S. Environmental Protection Agency (EPA) estimates that four million persons reside, and about six hundred K-12th grade schools are located, within 500 meters of PEA servicing airports (EPA, 2020b). Zahran et al. (2017a) estimate
that sixteen million persons – and about three million children – live within a kilometer of such airport facilities. The disposition of aviation gasoline around such airports may be a meaningful source of child lead exposure. To date, two studies have explicitly statistically linked aviation gasoline usage to blood lead levels of children residing in the vicinity of general aviation airports, showing the child BLLs increase in proximity to general aviation airports and increase dose-responsively with the volume of piston-engine aircraft traffic at general aviation airports. READ MORE

Excerpt from Penn State: In parallel with the educational efforts, the committee recommended continued scientific pursuit of new technologies, including lead-free propulsion systems such as electric or hydrogen-powered aircraft. The transition to next-generation small aircraft may require congressional initiatives, according to the report, such as policy requiring all new aircraft produced 10 years from now to run on unleaded fuel. READ MORE