Credit: Bo Zhang

The toxic effects of lead on both the environment and human health are no longer front-page news. Since the Environmental Protection Agency (EPA) started to phase out leaded gasoline in automobiles 30 years ago, thousands of tons of lead have been kept out of the environment.

But while the situation has seemingly improved, few people are aware that most commercial airplanes, except for jets, are still using fuel containing lead. The fuel  is commonly known as 100LL (100 low lead), and it contains 2.2 grams of lead per gallon. The EPA’s National Emissions Inventory estimated that lead emissions from leaded aviation gasoline, or “avgas” – were 491 tons in 2002, and accounted for 29 percent, the largest emitting source of air pollution from lead. The use of leaded avgas not only affects the air, but also threatens the surrounding regions. “People living close to the airports have expressed concerns about possible adverse health effects from lead,” said Martin Rubin, director of the Concerned Residents Against Airport Pollution organization.

Lead has long been recognized as causing serious adverse health effects. It can damage the immune system, cardiovascular system, kidney, bones and teeth, it can even cause brain disorders (especially in young children). Symptoms of lead poisoning in humans include poor memory, irritability, insomnia and lowered IQ. More than 6,000 studies on lead’s health and environmental effects have been published since 1990, and all of them show there is no safe level of lead in the human body.

But there is much controversy surrounding whether or not leaded gas-using airplanes are actually affecting human health. According to Tom Kramer, an aviation technical specialist at Aircraft Owners and Pilots Association (AOPA), leaded fuel used in general aviation only accounts for a “miniscule fraction” of total fuel in this country. So the health effects are almost “negligible”. While the overall amount of lead emission is much smaller than it was 30 years ago, “for those people living around the airport it’s not negligible,” said Danielle Fugere, a regional program director of Friends of the Earth (FOE) – an environmental organization. Unfortunately, this issue has been minimally researched.  “We know that lead is a human health harm and has significant impacts,” Fugere said. “If you don’t need to introduce lead to the environment, you should not.”

A Swissport employee fuels a Southwest Airlines plane at the Oakland International Airport October 16, 2008 in Oakland, California. Credit: PicApp.com

The U.S. military first began using leaded fuel in aircrafts in the 1930’s. The use of a leaded fuel protects airplane engines from detonation, or “knock,” which causes an engine to tear itself apart during flight. Lead also protects engine components from long-term damage caused by high pressure. It is able to do this by increasing octane, which allows the use of higher compression engines that produce more horsepower. Because of these advantages, even today’s new airplanes are designed around engines relying on 100LL.

But despite the benefits, concern over lead’s impact on the environment and human health has led dozens of organizations, including the Federal Aviation Association (FAA), to try to develop an alternative fuel to phase out lead from the current avgas. According to a 2008 report by Aircraft Owners and Pilots Association (AOPA), 70 percent of the general aviation fleet could run on a lower octane gas that has no added lead. They’ve been working on a lead free avgas solution since the 1990s.

However, the fuel replacement plan is undertaking an arduous journey. “The challenge is finding a fuel with the same properties that will not require substantial modifications to existing engines,” said Tom Kramer, an aviation technical specialist at AOPA. Unlike the auto industry that can implement engine design changes very quickly, the aviation industry has to change engine combustion system and ignition units to adjust to unleaded fuel.

Besides seeking an alternative fuel, officials are also working on new regulations for emissions. Friends of the Earth (FOE) petitioned the EPA in 2006 to study the impact of leaded fuel in aviation. “Since most of these planes can fly on non-leaded gasoline, there should be a standard going forward,” Fugere said.

On October 15, 2008, the EPA strengthened the national ambient air quality standards (NAAQS) for lead substantially. “The revised standards are 10 times tighter than the previous standards,” said Justin Cohen, an official from EPA’s Office of Transportation and Air Quality, “it will improve health protection for at-risk groups, especially children.”

Air Atlanta L.1011 Tristar TF-ABT. Credit: FreeFoto.com

Moreover, the EPA has been taking air and soil samples at Santa Monica Airport and in surrounding neighborhoods to test for ambient lead levels. “We certainly would want to know how much lead is coming from that airport,” said Rubin from Concerned Residents Against Airport Pollution. The study is intended to create a model for evaluating lead levels at airports. And the results could help the EPA respond to the FOE petition and also help federal officials formulate new regulations for lead emissions.