As part of Sen. Cory Booker’s presidential primary campaign, the New Jersey Democrat talks about "environmental justice" — which seems to mean addressing the environmental factors that disproportionately affect people who are low-income and from minority backgrounds.
One issue he’s highlighting: the impact of so-called Superfund sites, hazardous waste sites that are especially prevalent in Booker’s home state, and usually located in the same neighborhoods as low-income residents, often African American or Hispanic.
In an April 29 interview with MSNBC, Booker cast that issue not only as a challenge for social justice and equality but also as a public health problem.
"We now have longitudinal data that shows that children born around Superfund sites have dramatically higher rates of birth defects, dramatically higher rates of autism," he said.
First, the data
Booker’s press team sent us two Superfund studies: a 2008 paper on the association between toxic landfills and autism spectrum disorders (ASDs) and a 2011 study probing that association regarding congenital anomalies (the "birth defects" Booker mentioned).
In the autism paper, researchers mapped the location of New Jersey Superfund sites and almost 500 children diagnosed with ASD from 1998 to 2006, finding that cases appeared in higher frequency closer to the sites. Those researchers also checked for a relationship between higher numbers of Superfund sites in a state and frequency of ASDs.
That analysis "reveal[ed] considerable overlap" between high Superfund rates and autism diagnoses — though the authors were quick to caution that a correlation didn’t mean one caused the other.
The 2014 paper looked at births from 1989 to 2003, near Superfund sites in Florida, Michigan, New Jersey, Pennsylvania and Texas — all of which were cleaned up at some point in that time frame. Before a site was cleaned up, infants were, on average, 20% to 25% more likely to have a congenital birth defect.
"This does suggest that the Superfund sites caused birth defects," argued Janet Currie, a study author and professor of economics and public affairs at Princeton University, in an email to KHN.
Both of these are longitudinal studies, meaning the research was collected over time to track patterns and changes.
Booker’s phrasing is quite deliberate – and that matters for his case
We spoke to environmental health researchers unaffiliated with the studies. They said it would be very difficult to prove that being born near a Superfund site causes kids to be born with birth defects, or causes autism. It helps that in his statements Booker doesn’t try to make that case. One caveat, though, is that a casual listener could draw that conclusion.
The studies he’s working with are "fairly exploratory," said David Savitz, a professor of epidemiology at Brown University’s School of Public Health. While they support the idea of a link between autism and Superfund sites, or birth defects and such sites, they don’t go so far as to support a case for causality. Other factors could contribute, too.
"It’s not hard to imagine all the ways the communities proximal to waste sites may be different — a lot of ways other than just having the waste site," Savitz said.
But Booker’s comments are rooted in legitimate data sources. Both those studies are peer-reviewed and suggest there could be some kind of relationship. So, the center of his claim — there is data that shows children near Superfund sites having higher rates of congenital abnormalities and autism — does, in fact, check out.
Even so, environmental health experts said, much more work is needed to understand the nature of that claim. Risk factors for autism are still not well-identified. And congenital abnormalities can refer to a range of different problems — so research that lumps them together may gloss over important distinctions, especially when it comes to what might cause a specific birth defect.
The bigger picture
Booker is getting at a larger truth: Many chemicals found at Superfund sites are related to health problems, the experts said. And, those same experts added, his environmental justice framing is one that makes sense, too, given the demographics of those most often affected.
From a policy standpoint, Savitz argued, Booker’s bigger point — that cleaning up Superfunds would improve health outcomes, in particular for marginalized people — is clearly true.
The only real issue, some suggested, is his use of the word "dramatically." The data suggests potential correlation, but whether it’s "dramatic" is far from clear.
"Certainly there is evidence to back up his claim," said Amanda Bakian, an assistant professor of psychiatry at the University of Utah, who studies environmental contributors to autism risk. "There’s been work finding an association, but the relationship is modest. … We do need more research in this area."
Booker is correct in saying data shows that children born near Superfund sites have higher rates of birth defects and autism. In this statement, he doesn’t specifically say there is a causal relationship — which is important, because the data does not necessarily say Superfund proximity causes those issues, and more research would be needed to support that claim.
The use of the word "dramatically" causes a bit of trouble, however. The datasets show statistically significant correlations. But that isn’t the same thing as a "dramatically higher rate."
The statement is true, but could use more context. We rate it Mostly True.
This fact check was reported and edited by Kaiser Health News. PolitiFact and KHN are partnering to fact-check claims about health care.