Residents and businesses near the Palo Alto Municipal Airport should be getting notifications about the use of leaded aviation gas at the airport, according to a legal settlement between an environmental-advocacy group and 30 suppliers of lead-containing aviation gas, including the local airport.
Aviation-fuel retailers must post signage regarding the danger of lead and warn residents within 1 kilometer (two-thirds of a mile) of the airport by letter or hand-delivered door hanger as part of the settlement. That includes a portion of East Palo Alto, businesses along the east end of Embarcadero Road and part of the Palo Alto Baylands Nature Preserve.
Palo Alto Airport fixed-base operator Rossi Aircraft Inc. is a signatory to the settlement, but the company's owner did not return requests for comment about plans to notify the public.
The Oakland-based Center for Environmental Health filed a lawsuit against the aviation-gas ("avgas") suppliers in October 2011 for allegedly failing to comply with California's Proposition 65.
Lead, which is added to aviation fuel to boost octane and improve performance in piston-engine aircraft, is linked to miscarriage, low birth weight and premature birth. It can cause increased heart and respiratory diseases, neurological disturbances, convulsions, muscle weakness, paralysis and cancer, according to the U.S. Centers for Disease Control and Prevention and the United Nations Environmental Programme.
But airport officials are quick to point out that lead particles are heavy and tend to drop near the site of takeoff or where planes are gearing up for flight. A 2011 Duke University study supports that assertion, noting that there was little increase in air lead from background levels beyond 1,500 meters.
The Duke study did find "a significant association between potential exposure to lead emissions from avgas and blood levels in children," however. Children living within 1 kilometer of airports had a 4.4 percent higher blood lead level compared to other children, with children living within 500 meters most greatly affected. The study was adjusted for other sources of lead in the children's environments, such as peeling lead-based paint.
But lead from avgas is minor compared to other sources such as lead-based paint from older buildings, leached lead from water pipes, and consumer products and toys manufactured in countries with less-stringent regulations, the researchers said.
In wildlife, and particularly in birds, lead shot ingestion and consuming contaminated fish are the prevailing sources of lead poisoning.
A June 2013 Environmental Protection Agency (EPA) preliminary report on airport lead emissions found that Palo Alto's three-month, average lead concentration in the air was 0.12 micrograms per cubic meter -- just below the EPA's National Ambient Air Quality Standard of 0.15 micrograms per cubic meter. (The San Carlos Airport exceeded the federal standard with a value of 0.33 micrograms, according to the report.)
The EPA study could play a role in policy changes related to leaded avgas. The agency is currently studying whether lead emissions from avgas endangers the public. A final determination is expected in mid-2015.
Local studies of leaded avgas pollution appear to be nonexistent. The Bay Area Air Quality Management District, which monitors pollutants, hasn't monitored for atmospheric lead for years. Monitoring pretty much stopped when lead ceased being added to automobile gasoline, which was considered the greatest source of lead in air, a spokesperson said.
Wildlife studies around San Francisco Bay have focused mainly on lead sources from ammunition.
Ralph Britton, president of the Palo Alto Airport Association, said he recognizes the risks of leaded fuel and talked about the economic challenges of developing alternative fuel.
"No one thinks using leaded fuel indefinitely is a good idea, but there is no viable alternative at the moment," he said. "That does not mean that it is unimportant to solve this problem, however. Because of the small demand, oil companies have little or no economic incentive to develop an alternative to processes already in place. In time, however, unleaded aviation gasoline will be available, but given the lack of economic incentive it will take some years," he said.