Although it’s long been known to be toxic to humans, leaded fuels are still used in 167,000 small aircraft in the United States, including those taking off at Renton Municipal Airport.
Small piston aircrafts use aviation gasoline (avgas) which is widely distributed and produced. It’s also the only remaining lead-containing transportation fuel.
This is a concern to South Renton Connection president Jeff Dineen, who presented his concerns to Renton City Council this year.
“Knowing that the Renton Airport is well over 100 years old, it is reasonable to conclude that the Renton Airport is responsible for hundreds of millions of grams of lead pollution with a disproportionate amount of it falling on your neighbors to your airport,” Dineen stated in his letter to council.
Dineen is not an expert, but he made what he calls “hypothetical calculations” using how much lead fuel is sold at the Renton Municipal Airport compared to the projected growth rate of flights at the airport, shown in the previous Airport Master Plan.
Dineen’s numbers have not yet been checked by city or airport staff. Airport Manager Harry Barrett said they haven’t been able to dig into the data yet due to staffing constraints, but he said they are tracking number of flights and plan to respond to Dineen.
While these numbers have not been checked by staff, it is true that the airport is selling lead fuels, and the small piston aircraft are using them. The Renton airport is one of a majority of airports in the United States that still sell leaded fuels for small piston aircraft.
What isn’t clear is how the emissions from the lead fuel impact those under the flight path, from houses to Renton High School to Lake Washington.
What the studies say
According to the Environmental Protection Agency’s 2014 National Emissions Inventory Report, Renton Municipal Airport generated the fourth-most lead emissions out of the 10 airports in King County, with 0.27 tons of lead emissions, or about 244,939 grams.
This fell slightly below Dineen’s estimate of 289,945 grams of lead emissions for 2014.
Auburn Municipal Airport, in comparison, came in first with almost a half-ton of emissions, or about 408,233 grams.
King County had the highest lead emissions in Washington state. Out of 2.13 tons of lead emitted that year in King County, 1.56 tons of it came from airports.
Currently the Renton airport does not have steps in place to removing leaded fuel, Barrett said, as it’s a regulatory process and they don’t want to take a “shotgun approach” that would be unsustainable for the airport’s fuel providers, Rainier Flight Services and Pro Flight Aviation.
“I won’t say there’s not a concern— there is obviously a concern there,” Barrett said. “I will say that industry-wide we are proactively working on it, and we hope to have some answers in very short order on how to get unleaded fuels mass produced and out to the pilots to use.”
The Federal Aviation Administration (FAA) has been working with Shell Oil Company and Swift Fuels on a solution to using unleaded fuel, but it’s taking longer than anticipated. And in September the FAA announced final testing of a fuel alternative is being postponed until the middle of 2020.
Swift Fuels also recently suspended its work on the FAA’s alternative fuels initiative, in order to pursue alternatives outside the program.
The light aircraft that do have unleaded fuel currently run less efficiently, Barrett said. He also said since those aircraft engines can’t accept the alternative fuel, they can’t require it of those using the airport runway.
Barrett said 35 percent of these aircraft require leaded fuel, according to industry-estimates. Some research suggests the industry estimate is more around 25 percent. The aircraft requiring avgas are mostly older vintage planes.
“About half of our aircraft here are vintage aircraft,” Barrett said.
At least eight airports sold unleaded fuels as of 2016. Barrett said he wasn’t familiar with these airports and how they sell alternative fuels, but was interested in learning more and that it was something the airport would need to look into.
Addressing residents’ worries
Dineen’s concerns were discussed at the Monday, May 6 Renton Transportation Committee meeting. Barrett told council while some companies are working on making unleaded fuels work in small aircraft, not much progress has been made.
Councilmember Ryan McIrvin asked Barrett if there was any examination of Dineen’s data to see if the emissions from leaded fuels were coming down on the neighborhoods in the flight path. All three councilmembers at the meeting said they would like the Renton airport to support or participate in studies or solutions.
At the meeting, Barrett said that while they did not check, University of Washington is doing a study on Seattle-Tacoma International Airport (Sea-Tac), that would also look at five airports. Barrett later said in an interview with the Reporter that while that study no longer intends to cover Renton, UW procured Renton airport data of flight numbers.
That study, Mobile ObserVations of Ultrafine Particles (MOV-UP), looks at the air quality from flight traffic generated by the airport. It’s similar to a 2014 study done at the Los Angeles International Airport, that found more particles were being emitted than previously thought.
When the objectives of the study were finalized by a proviso in the Washington state budget, which funded MOV-UP, it was determined they would only look at the cities under the flight path and 10 miles around the international airport. This goes from Federal Way up to Beacon Hill.
Edmund Seto is a University of Washington Associate Professor and Principal Investigator for MOV-UP. He said the ultrafine particles are a kind of air pollution that is known to have health impacts in airport communities from previous studies, and was originally a concern for busy streets.
Burning any fuel has a tendency to create these particles, Seto said, and it was only in recent years people have paid attention to emissions of these particles outside of our roadways.
Seto said these ultrafine particles can be bad for folks with cardiac or respiratory issues, including older people or people with asthma, and research is looking into if it is also connected to several types of cancer.
The current study of Sea-Tac airport is focused on documenting particles, not the health of those living in the flight path, Seto said. MOV-UP will finalize the report by December 2019.
Barrett said he hopes the study will help him understand the true impacts of particle emissions and how Renton airport can improve on those results to better the aviation community.
While Seto said he wasn’t familiar with Renton’s airport, it’s well-known lead is a toxic compound, and phasing out lead use in vehicles resulted in decreased blood-lead levels in children.
“Generally, lead is one of the most toxic things that affects humans, particularly children in developmental stages,” Seto said. “That’s why for decades we’ve struggled to remove lead from all products.”
Seto said it’s a concern at whatever extent leaded fuels are being emitted, and needs to be considered.
On Monday, May 20, U.S. Rep. Adam Smith introduced, for the second time to congress, legislation titled the “Aviation Impacted Communities Act,” which would create a better process for those under aviation flight paths to interface and petition the FAA for impact studies.
Smith stated in written testimony that this legislation would also mandate a national study of some of the busiest airports in the country, including Sea-Tac airport, in the district he represents.
“Residents of impacted communities across the country, like those in the congressional district I represent, deserve to know how they are affected by ultrafine particles in the atmosphere, where these particles originate from and whether alternative fuels such as biofuels could be employed to reduce those impacts,” Smith stated.
All the while residents who, like Dineen, continue to live under the flight path are asking what is happening not just above and but also below, since lead doesn’t break down— it stays in the soil over time.
“When does the city, as the owner of the airport, start listening to the concerns of its neighbors to its airport?” he stated in an email.
A 2013 fact sheet on why leaded fuels are still used in small aircrafts is available here.
