MPH 506 Week 5 Case Study Analysis Example

Case Study Analysis: How Santa Clara County Ended Leaded Fuel Sales at Reid-Hillview Airport, Judged Against What Was Known at Each Step

Student Name

Chamberlain University

MPH 506: Environmental Health in Public Health

Instructor Name

Month Day, Year

Case Study Analysis: How Santa Clara County Ended Leaded Fuel Sales at Reid-Hillview Airport, Judged Against What Was Known at Each Step

The Case and Why It Was Chosen

Reid-Hillview Airport is a county-owned general aviation airport in East San Jose, California, surrounded by dense residential neighborhoods that are predominantly Latino, with about 13,000 children living near it (Cabrera, 2022). In August 2021, the Santa Clara County Board of Supervisors voted to end the sale of leaded aviation fuel at its two airports, effective January 1, 2022, after a county-commissioned study linked the airport to higher blood lead in nearby children (Cabrera, 2022; Zahran et al., 2023). The case is relevant to the composite Harmon Field analysis in this course because it is the clearest example of a local government acting on aircraft lead before federal rules existed, and because it shows both what a county can do and where its authority runs out.

A Timeline of What Was Known

The analysis separates three periods, because the knowledge available changed sharply between them.

Table 1

What Was Known and Decided About Aircraft Lead, by Period

Note. Note. Dates and decisions from Cabrera (2022), Zahran et al. (2023) and U.S. Environmental Protection Agency (2023).

Judged against the first period, inaction by a county is understandable: the pathway was plausible but no local or national evidence tied it to children's blood. Judged against the second, the county's choice to commission a local study rather than act on the North Carolina results was cautious but defensible, since the North Carolina effect was small and came from a different setting. By the third period, the county had evidence from its own children, and acting on it was a reasonable use of the information then in hand.

The Pathway, Traced

The case fits the five-link pathway used earlier in this course. The source was piston aircraft running on leaded fuel, especially during run-up and takeoff. The medium was air and then soil. Exposure points were homes and schools close to and east of the airport, downwind under prevailing winds. The route was ingestion of soil and dust and some inhalation. The receptor was young children. What made the case unusual was evidence on the last link: the county study found that children's blood lead tracked the volume of piston traffic and fell during the pandemic, when traffic dropped (Zahran et al., 2023). That natural experiment strengthened the causal case in a way that proximity alone could not.

Outcomes the Case Supports

The case supports three outcomes. It supports a link between airport lead and children's blood lead at the population level, with increases that are small for each child. It supports the feasibility of ending local sales of leaded fuel, since an unleaded 94-octane fuel was offered in its place. And it supports the finding that local action provokes federal resistance. The case does not yet support a claim that the ban lowered children's blood lead, because published follow-up data were not available in the sources reviewed, and planes can still arrive with leaded fuel bought elsewhere.

Failures, Kept Apart by Type

Three distinct failures shaped the case, and they need different remedies.

Technical. No single unleaded fuel was approved for every piston aircraft at the time of the ban. The 94-octane fuel offered was certified for roughly two thirds of the aircraft using the county airports, according to reporting at the time (Cabrera, 2022). Pilots of high-compression engines had to fuel elsewhere, which limited the ban's effect on emissions.

Regulatory. Lead was removed from automobile gasoline decades earlier, but the federal process for aircraft moved slowly; EPA's endangerment finding came only in 2023 and did not itself restrict fuel sales (U.S. Environmental Protection Agency, 2023). For years, communities near airports had no federal rule to rely on.

Institutional. Airports that have accepted federal grants agree to conditions on how they operate, and the federal aviation agency opened an investigation into whether the county's ban was consistent with those obligations, asking the county to suspend it (Cabrera, 2022). The county's authority as airport owner was real but limited by those agreements.

What Would Have Changed the Outcome

An approved unleaded fuel for the whole fleet, available earlier, would have removed the technical barrier and much of the institutional conflict, since a ban is easier to defend when every aircraft has a safe alternative. A federal rule on aircraft lead within a few years of the North Carolina findings would have spared counties from acting alone. Locally, routine blood lead testing mapped by distance from the airport, started before 2021, would have given the county a baseline against which to measure the ban's effect.

What Transfers to Other Places

For Brennan County and Harmon Field, three lessons transfer. First, a county should collect local evidence, as Santa Clara did, because federal action may lag and local data make a decision defensible. Second, steps within the county's clear authority, such as moving a run-up area away from homes or offering unleaded fuel alongside leaded at the county fuel farm, can reduce exposure without the conflict a ban brings. Third, physicians and community groups can carry the issue, as a physician advocacy group did around a San Diego airfield (Gilbertson et al., 2023). What does not transfer directly is the ban itself, whose legal standing depends on federal grant obligations that each airport must review with counsel.

A final point concerns evidence. Santa Clara County could act in 2021 because it had commissioned a study of its own children, and that study gained force from a pattern no one had planned, the drop in piston traffic during the pandemic. Brennan County cannot count on such an accident, so it should plan its own before-and-after measurement now, before any change at Harmon Field.

References

Cabrera, Y. (2022, February 15). A California county moves to protect children from lead poisoning, but some aren't ready for the solution. Grist. https://grist.org/transportation/california-county-bans-toxic-aviation-fuel-at-its-airports/

Carr, E., Lee, M., Marin, K., Holder, C., Hoyer, M., Pedde, M., Cook, R., & Touma, J. (2011). Development and evaluation of an air quality modeling approach to assess near-field impacts of lead emissions from piston-engine aircraft operating on leaded aviation gasoline. Atmospheric Environment, 45(32), 5795-5804. https://doi.org/10.1016/j.atmosenv.2011.07.017

Gilbertson, R., Friedman, E., Nguyen, V. T., Stahl, S., & Ireland, R. (2023). The role of physician advocacy in supporting policy change that reduces leaded aviation gasoline emissions. Journal of Community Health, 48(3), 446-449. https://doi.org/10.1007/s10900-023-01186-9

Miranda, M. L., Anthopolos, R., & Hastings, D. (2011). A geospatial analysis of the effects of aviation gasoline on childhood blood lead levels. Environmental Health Perspectives, 119(10), 1513-1516. https://doi.org/10.1289/ehp.1003231

U.S. Environmental Protection Agency. (2023). Finding that lead emissions from aircraft engines that operate on leaded fuel cause or contribute to air pollution that may reasonably be anticipated to endanger public health and welfare (Final rule, 88 FR 72372). https://www.federalregister.gov/documents/2023/10/20/2023-23247/finding-that-lead-emissions-from-aircraft-engines-that-operate-on-leaded-fuel-cause-or-contribute-to

Zahran, S., Keyes, C., & Lanphear, B. (2023). Leaded aviation gasoline exposure risk and child blood lead levels. PNAS Nexus, 2(1), Article pgac285. https://doi.org/10.1093/pnasnexus/pgac285