Valley fever is caused by the fungus Coccidioides, which lives in arid soils and becomes airborne when disturbed. A new study from UC Berkeley is the first to use individual patient records to show that living near oil and gas well construction raises the risk of contracting the disease. The researchers compared anonymized California public health data—including residence coordinates and case dates—against the timing and location of new well development in Kern County from 2007 to 2022.
They found that people living within 3 miles of a well had a 12.5% higher risk of valley fever during the 90 days after construction began, likely due to dust stirred up by site preparation and drilling. Nearly three in four Kern County residents live within that radius. The study's lead author, Lisa Couper, said the effect was detectable up to 5 kilometers away, suggesting that California's 2024 law requiring a 1 kilometer buffer between new wells and homes may be too small.
The risk is not limited to oil and gas: a solar farm installation in Monterey County in 2016–2017 caused an outbreak among construction workers. With no vaccine and only a few antifungal treatments, prevention is critical. The researchers emphasize using dust controls, home air filters, and N95 masks in at-risk regions, since valley fever can be fatal if the fungus spreads beyond the lungs.