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Study Commissioned by County of Santa Clara Finds Increased Lead Levels in Children Living Near Reid-Hillview Airport

Comprehensive and controlled study reviewed 10 years of data; findings include that blood lead level increases in children downwind from the site are similar to those seen in the Flint, Michigan, Water Crisis

​​SANTA CLARA COUNTY, CALIF.— A study commissioned by the County of Santa Clara on lead exposure risks for children living in the area around Reid-Hillview Airport in East San José found that the continued use of leaded aviation fuel has contributed to increased blood lead levels, particularly for those within a half-mile of the facility.

The peer-reviewed study found that children living downwind from the airport had higher blood lead levels, with increases of .40 micrograms per deciliter, over children living upwind from the airport. For context, lead levels detected during the peak of the Flint Water Crisis were between .35 and .45 micrograms per deciliter over baseline.

The study also examined levels during times of maximum exposure to air traffic for children within a half-mile of the airport and estimated an increase of .83 micrograms per deciliter at peak times – significantly higher than the levels seen in Flint.

Children who live within a half-mile of the airport had blood lead levels 20% higher than children living between half-mile to 1.5 miles from the airport. The study also correlated blood lead levels with the proximity of a child’s home and school to Reid-Hillview Airport. Children who commute toward Reid-Hillview to attend school present substantially higher blood lead levels than children who commute away from the airport.

Health organizations agree that there is no known safe level of lead in a child’s blood, and exposure to even a small amount of lead has a negative effect on cognitive ability, particularly in developing children who absorb lead more efficiently than older children and adults.

The study was conducted by Dr. Sammy Zahran and the Mountain Data Group. It incorporated three main tests of exposure risk and was controlled for other sources of lead exposure.

The study is available online. The County will hold two Zoom community meetings next week – one for neighborhoods surrounding Reid-Hillview, a second for South County residents near San Martin Airport – to present the findings of the study and receive questions.

East San José Community Meeting

  • Wednesday, August 11, 6 pm
  • Join webinar (on Zoom):
  • You may also call into the meeting by smartphone at: (669) 219-2599, Webinar ID 93339943986# (participant ID not required)
  • The meeting will be translated simultaneously in Spanish and Vietnamese.

South County Community Meeting

  • Thursday, August 12, 6 pm
  • Join webinar (on Zoom):
  • You may also call into the meeting by smartphone at: (669) 900-6833, Webinar ID 95709413535# (participant ID not required).
  • The meeting will be translated simultaneously in Spanish and Vietnamese.

“This important study helps us understand General Aviation airplane emission impacts to cognition and health of nearly 13,000 children who live within the 1.5-mile Study Area.” said Deputy County Executive Sylvia Gallegos. “We encourage everyone to review the findings and ask questions or share their thoughts.”

Since the elimination of lead in automotive fuel in 1996, aviation fuel (referred to as “avgas”) used by 170,000 piston-engine aircraft nationwide has become the largest source of lead emissions. Avgas accounts for half to two-thirds of current lead emissions in the nation.

In December 2018, the Board of Supervisors voted to stop accepting federal grants for Reid-Hillview Airport, which would extend the County’s obligation to operate an airport.

Recommendations based on the Reid-Hillview Airport Airborne Lead Study will be presented to the Board of Supervisors at its August 17 meeting at 6pm.


The County of Santa Clara government serves a diverse, multi-cultural population of 1.9 million residents in Santa Clara County, California, making it more populous than 14 states in the U.S. The County provides essential services to its residents, including public health protection, environmental stewardship, medical services through the County of Santa Clara Health System, child and adult protection services, homelessness prevention and solutions, roads, park services, libraries, emergency response to disasters, protection of minority communities and those under threat, access to a fair criminal justice system, and many other public benefits.

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Media Contact: María Leticia Gómez/Eric Kurhi, (408) 299-5119, [email protected]