Lead was removed from gasoline decades ago. So why is aviation fuel still laced with the metal – a neurotoxin tied to developmental problems in children?

Veronica Licon and her pediatrician were stumped in 2011 when her son's blood showed high levels of lead. Her home did not contain the usual culprits for childhood lead poisoning: lead paint or lead pipes.

Paint can be removed. Pipes can be replaced. But Licon lives directly under the flight path to Reid-Hillview Airport in East San Jose, Calif. The small airplanes and choppers flying overhead run on leaded gasoline, dusting her home with a neurotoxin research links to lowered IQ and behavioral problems in children. There's nothing Licon can do about that.

She's haunted by the long hours spent at home while pregnant with her youngest daughter, a now 12-year-old girl plagued by learning delays.

Today, toddlers in East San Jose have concentrations of lead in their blood on par with children tested at the height of the drinking water crisis in Flint, Mich., according to a recent study done in coordination with the California Department of Public Health. Meanwhile, aircraft in and out of the airport are flying on leaded gasoline three decades after the U.S. banned the fuel for cars.

Efforts since then to develop unleaded, or even less heavily leaded fuel for small airplanes, have been dependent on the approval of oil and aviation experts who meet through the nonprofit standards organization ASTM International. Whether the inventor was from a maker of piston-engine airplanes or a Swedish chemist, a new formula for lead-free gasoline went first to a committee that included fuel producers like Chevron and Exxon Mobil. And the panel has repeatedly rejected proposals to create unleaded fuels for small aircraft, an investigation by POLITICO's E&E News found.

As a result, the Federal Aviation Administration has failed over multiple administrations to achieve a policy goal to move American fliers to cleaner fuels. And major oil companies have protected their small-but-profitable market for leaded aviation gas, according to interviews with nearly a dozen former members of the fuel-standards committee and documents reviewed by E&E News.

In 1999, Swedish inventor Lars Hjelmberg had a pitch for FAA regulators who had flown to Brussels to hear more about his lead-free aviation gasoline formula.

When FAA officials arrived in Brussels, Swedish pilots had been flying on the medium-octane fuel for eight years. The safety record spoke for itself. "It was a good fuel," recalls a former FAA official who requested anonymity to talk in detail about the meeting.

"All Lars needed was a U.S. company on board with him," the official said. "But they didn't want to, and we at FAA could not speak for the industry."

Today, the vast majority of Sweden's small planes fly on unleaded gas. But Hjelmberg and the FAA had a problem. An effort to bring his fuel to the U.S. market had been turned away earlier in the decade when an ASTM standards committee pointed to efforts by U.S. companies to develop a higher-octane fuel. And it would fail again in 1999 because no U.S. oil refinery would agree to produce it, Hjelmberg said.

"FAA trusted the large U.S. oil companies more than they trusted me," Hjelmberg said.

"The FAA and the aviation industry see ASTM approval as a critical safety check. Engine-makers, pilots, community airports and FAA officials sit on ASTM's piston-engine aviation fuel standards subcommittee. So do representatives for the major oil companies that operate U.S. refineries. A committee requires a consensus to write a new standard and bring a fuel to market. That allows a company with a vested interest to block a competing fuel, according to former members of the panel."

"The question asked in ASTM meetings is, essentially, 'What is in this for my company?'" said Paul Millner, a former Chevron fuel engineer who sat on the ASTM panel. '"And if we do need a new specification, how do I craft this thing so that if it hurts anybody, it hurts my competitor more than me.'"

Hjelmberg's 96-octane unleaded formula, first introduced in 1991, wasn't the only new fuel rejected by the panel. In the same time period, a 95-octane unleaded formula from the Wichita, Kan.-based aircraft-maker Cessna also didn't make it through the process.

Had it been approved, Cessna planned to modify much of its fleet to fly on the cleaner gas. But the company stopped work on the fuel in 2002 after being rejected by the standards committee according to a presentation given by the project's chief scientist years later.

"General Aviation Modifications Inc., or GAMI, a small aerospace company in Oklahoma, started working on a 100-octane zero-lead formula in 2009. It found the secret sauce within nine months, said George Braly, the aeronautical engineer who founded the company.

GAMI the next year asked the FAA to certify that airplanes can fly on the fuel. Braly got his initial approval from the agency last summer – 12 years later."