A piston-engine aircraft flies against a cloudy sky
Roughly 170,000 piston-engine aircraft are used across the country. Nearly all burn a grade of aviation gasoline that contains lead. (Nicolas Economou/NurPhoto via Getty Images)
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The country began phasing lead out of gasoline for cars in the mid-1970s, and yet the toxic metal is still in aviation fuel for small aircraft — spewing over neighborhoods with children especially vulnerable to its irreversible impacts.

That’s finally poised to change.

Following decades of pressure from environmental-justice advocates, the Federal Aviation Administration has authorized the use of a high-octane unleaded aviation gasoline for use in all spark-ignition aviation engines in the nation’s general aviation fleet. The agency described the decision as “a major step forward” to safely phase out leaded aviation fuel, which contains a highly toxic additive known as tetraethyl lead. 

The performance-enhancing additive prevents engine knock that can lead to sudden engine failure.  But its toxicity has been known since the 1920s, when scientists and health experts warned the federal government in public hearings of the dangers of using it in gasoline fuel. Its decision, announced on Sept. 1, marks the first time the agency has certified a high octane unleaded fuel for use in a majority of engines and aircraft, but it’s expected to take several years for the fuel to become widely available.   

The announcement comes nearly 20 years after one environmental-health coalition began petitioning the Environmental Protection Agency to regulate leaded aviation gasoline emissions from piston-engine aircraft. That has yet to happen. Earlier this year, the EPA announced plans to issue a finding that would classify leaded aviation gasoline air pollution as a danger to public health and the environment, but even then, the process of enacting regulations could take years. 

Time is not on the side of children exposed daily to lead, which harms their developing brains and nervous systems. That’s why earlier this year, Santa Clara County in the Silicon Valley instituted what its officials say is the nation’s first ban on the sale of leaded aviation fuel.

The decision impacts two county-owned general aviation airports, Reid-Hillview Airport and San Martin Airport, to protect residents who live and work in the surrounding neighborhoods. 

The county’s decision to act more quickly than the FAA triggered the ire of the agency. The FAA launched what it termed an informal investigation into the Jan. 1 ban, putting pressure on the county to delay its implementation. 

That didn’t sit well with U.S. Rep. Ro Khanna, a Democrat whose district includes San Jose, where Reid-Hillview Airport is located. 

U.S. Rep. Ro Khanna. (Andrew Harnik via Getty Images)

He described the FAA’s unleaded fuel announcement as a step in the right direction. But the move falls short of protecting America’s children from further lead exposure, he said. 

“In my district with blood lead levels that are higher than in Flint, Michigan, it’s unconscionable,” Khanna said. “The FAA needs to start caring about kids with poison in their blood. They’ve been indifferent. They’ve been dragging their feet. They’ve been unresponsive, and it’s outrageous. That needs to change.” 

The FAA said in a statement that it “remains committed” to efforts to develop, refine and distribute unleaded aviation fuel and is working with Santa Clara County “to reach a mutually acceptable implementation timeline.”

“The FAA is taking action now to create a lead-free future,” the agency’s statement said.

There are roughly 170,000 piston-engine aircraft estimated to be in use across the country, and nearly all burn a grade of aviation gasoline, commonly referred to as avgas, that contains lead. These aircraft include airplanes and helicopters used for a myriad of purposes — including fighting wildfires, agricultural crop dusting, pilot training, medical transport, search and rescue, pipeline inspections and law enforcement — that operate out of more than 13,000 airports

Khanna held a congressional hearing in late July on the dangers of leaded aviation gasoline, spotlighting the inequities faced by low-income residents and communities of color who disproportionately live near these airports across the country. He called for a nationwide ban on leaded fuel. 

“It’s wrong that almost 6 million people — many children — are still exposed near airports to leaded fuel in this country,” Khanna said.  

Santa Clara has refused to back down from its position, despite the FAA’s insistence that the county is obligated to sell leaded fuel, said County Supervisor Cindy Chavez. A 2021 county-commissioned study showed that children in the predominantly Latino neighborhoods around Reid-Hillview Airport in East San Jose are being poisoned by lead. She pointed to that as one of the primary reasons the county has remained steadfast. 

Santa Clara County Supervisor Cindy Chavez. (Photo courtesy of Santa Clara County)

“We take the position that, now that we know that we have a known toxic contaminant that’s coming from the two airports that we own and operate, that we have an obligation to be health protective of the community,” Chavez said.  

Lead exposure is ‘an absolutely urgent problem’

The scientific consensus is that no lead level is safe for children. Experts say that the cascade of harms for exposed children makes immediate action imperative. Research has shown that elevated blood lead levels can lead to increased aggression, lack of impulse control, hyperactivity, inability to focus, inattention and delinquent behaviors. Even children with low levels of lead exposure can experience serious consequences such as cognitive deficits, behavioral issues and educational delays.

“It’s just so wide reaching that it’s an absolutely urgent problem,” Simon Fraser University Professor Bruce Lanphear, an epidemiologist and leading expert on early childhood exposure to lead, testified during the hearing. 

Research has shown that reducing piston-engine aircraft traffic fueled by leaded gas would generate massive societal benefits, increasing children’s lifetime earnings. Lanphear’s research has shown that children with low to moderate blood lead levels experience the most IQ point loss, a finding that underscores the need to protect children from chronic exposure during the early years of life. 

A study released earlier this year found that half the U.S. population was exposed to high levels of lead during childhood in the last half of the 20th century. This resulted in a significant impact on brain development, which in turn resulted in a massive loss of IQ points for Americans born between 1951 and 1980, according to researchers from Florida State and Duke universities.  

Reid-Hillview Airport is surrounded by more than 20 sites with especially sensitive populations, including child care centers, elementary schools, after-school centers and parks. Santa Clara County officials also found that the communities surrounding the airport face challenges that make them more vulnerable to lead poisoning. 

In a letter to the FAA, the county counsel’s office outlined some of these risks, including low income and higher mortality rates related to cancer, Alzheimer’s disease, strokes, diabetes and hypertension than in surrounding communities. 

These factors “underscore why this is one of the most urgent environmental justice crises in the nation,” wrote Santa Clara County Counsel James Williams and County Executive Jeffrey Smith in a January letter to the FAA defending the ban. 

In making their decision, county officials also considered risks posed by Reid-Hillview Airport’s traffic levels. It’s one of the busiest general aviation airports in the country. It’s also used extensively for flight training, which means new pilots take off and land repeatedly, and circle around the airport, showering the densely populated residential neighborhoods in the flight path with lead pollution. 

The airport’s runways can accommodate only smaller aircraft, so most of its air traffic consists of lead-emitting piston engine aircraft. The county found that the airport’s ratio of lead emissions per person living within a mile of its location is the third highest in the nation. 

In 2017, these small, gasoline-powered general aviation aircraft comprised by far the largest single source of lead air emissions in the United States, generating 468 tons of it, according to EPA data. More than 5 million people, including 363,000 children under age 5, live less than a third of a mile from these airport runways, and more than 160,000 children attend school in these areas, a 2020 EPA analysis found. 

One 2017 study cited research showing that three-quarters of the nation’s piston-engine fleet could safely transition to lead-free automotive gasoline at little cost, but that these planes relied on leaded avgas because it’s the primary fuel available in most U.S. airports. 

There’s also a grade of unleaded avgas already available for certain aircraft, lower octane than what the FAA just approved. In its letter to the agency in January, Santa Clara County noted that a substantial portion of aircraft operating out of Reid-Hillview could use that avgas, and some were doing so.  

The National Academies of Sciences, Engineering, and Medicine issued a congressionally mandated report last year that concluded that “significantly” reducing lead emissions from gasoline-powered aircraft would require leadership and strategic guidance from the FAA as well as a sustained commitment from other government agencies working with pilots, airports, suppliers and aircraft manufacturers. 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 should be taken to begin reducing lead emissions and exposures, the report’s authors recommended. 

Since the ban’s implementation in Santa Clara County, the transition has been seamless, Chavez said. It includes a protocol to transport leaded gasoline to Reid-Hillview for aircraft that might need that fuel in emergency situations. Other counties have reached out to Santa Clara officials to learn about the ban and peer-reviewed, independent study on the exposure risks of leaded avgas, she said. 

“We think that it is critical, critical, critical that everybody have the same information, especially counties that wouldn’t have the resources to be able to invest in such a thorough study,” Chavez said. 

She thinks the FAA’s attention to Santa Clara’s ban suggests that the ripple effects of the county’s decision may extend far beyond its borders.  

Many cities and counties likely have their own version of a Reid-Hillview Airport but don’t have the means to commission a study like Santa Clara County, she noted. 

“We know that there are millions of children that live within zones of airports that absolutely mean they are currently being poisoned by lead, period, and that we have an opportunity to fundamentally change the health outcomes for millions of people,” Chavez said. 

She described the FAA’s announcement on the unleaded fuel alternative as a game changer, and credited Khanna for putting pressure on the agency by holding the July hearing. 

Among those testifying were the developer of that fuel, George Braly of General Aviation Modifications Inc., an aerospace engineering company in Oklahoma. A frustrated Braly told people at the hearing that he had been waiting for 147 days for the FAA to give the final signoff on the fuel. 

“The implications of this are that there’s more unleaded avgas available nationally,” Chavez said of the approval finally arriving. “I think that will make a significant difference to the community because consistent fuel is really what we need.” 

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Yvette is a senior reporter at the Center for Public Integrity covering inequality in economic and social...