5,500 U.S. Toxic Sites at Flood Risk, Study Finds

More than 5,500 hazardous sites across the U.S. are projected to be at risk of coastal flooding by 2100, according to newly published research led by University of California scientists.

The researchers found that if heat-trapping pollution grows unchecked, rising sea levels will flood a wide range of sites, including facilities that handle sewage, toxic waste, oil and gas, and other industrial pollutants, posing serious threats to public health and neighboring communities. The peer-reviewed study — Sea level rise and flooding of hazardous sites in marginalized communities across the United States – was just published in the London-based scientific journal Nature Communications.

"Flooding from sea level rise is dangerous on its own, but when facilities with hazardous materials are in the path of those floodwaters, the danger multiplies," said Lara Cushing, holder of the Jonathan and Karin Fielding Presidential Chair in Health Equity, and an associate professor of environmental health sciences with UCLA's Fielding School of Public Health. "This analysis makes it clear that these projected dangers are falling disproportionately on poorer communities and communities that have faced discrimination and therefore often lack the resources to prepare for, retreat, or recover from exposure to toxic floodwaters."

The researchers examined the 23 U.S. states with ocean coastlines and Puerto Rico and found the threat is not evenly distributed; seven states — Florida, New Jersey, California, Louisiana, New York, Massachusetts and Texas — account for almost 80% of the hazardous sites at risk by 2100. Much of the risk is already locked in due to past emissions, and nearly 3,800 hazardous facilities are projected to face flood risk as early as 2050, researchers said.

The study not only identifies toxic sites at risk from coastal floods but also analyzes who lives nearby. The findings revealed that certain communities are more likely to live near at-risk sites. Neighborhoods with one or more of these at-risk facilities, under a high-emissions scenario, have higher proportions of renters, households living in poverty, residents who identify as Hispanic, linguistically isolated households, households without vehicles, seniors and non-voters than neighborhoods without at-risk facilities.

The analysis is based on projections of a flood with a 1% annual chance of occurrence, commonly known as a 100-year flood event, under two emissions scenarios: a high-emissions scenario (RCP 8.5) and a lower-emissions scenario (RCP 4.5). The methodology was co-developed with an advisory committee, including both public health experts and community leaders in the coastal communities.

"Coastal communities, including underserved groups that are working to fortify their resilience to climate change need access to critical data and resources to plan for the future," said Rachel Morello-Frosch, an environmental health scientist and professor in the department of environmental science, policy and management at UC Berkeley's School of Public Health and a study co-author.

The authors note that moderate cuts to climate pollution could reduce the number of sites at risk by more than 300 by the end of the century.

"There are potential solutions, if policymakers are ready to move forward," Morello-Frosch said. "And there is a clear need for disaster planning and land-use decision-making, as well as mitigation strategies to address the inequitable hazards and potential health threats posed by sea level rise."

Methodology

The analysis included four steps:

• The identification of coastal hazardous site locations and the cleaning of associated descriptive data.
• The estimation of future flood risk due to sea level rise at each site location
• The compilation of measures of demographics and social marginalization.
• A neighborhood-level analysis of the relationship between these measures and residential proximity to at-risk sites.