States: The threat is heavily concentrated in seven coastal states: Florida, New Jersey, California, Louisiana, New York, Massachusetts and Texas (Photo Credit: UCLA Fielding)
More than 5,500 hazardous sites across the United States are projected to be at risk of coastal flooding by 2100, with poor and marginalized communities facing disproportionate danger, according to new research published Monday.
The peer-reviewed study, led by University of California scientists and published in Nature Communications, warns that rising sea levels will flood facilities handling sewage, toxic waste, oil and gas, and other industrial pollutants if heat-trapping pollution continues unchecked.
"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 Dr. Lara Cushing of UCLA's Fielding School of Public Health.
The threat is heavily concentrated in seven coastal states — Florida, New Jersey, California, Louisiana, New York, Massachusetts and Texas — which account for nearly 80% of the hazardous sites at risk by century's end.
Much of the danger is already inevitable due to past emissions. Researchers project nearly 3,800 hazardous facilities will face flood risk as soon as 2050, regardless of future climate action.
The study examined 23 U.S. states with ocean coastlines plus Puerto Rico, analyzing projections of floods with a 1% annual chance of occurring — commonly called 100-year flood events — under both high and lower emissions scenarios.
Disparities in Risk
Beyond identifying at-risk toxic sites, the research reveals stark demographic patterns in who lives nearby. Under a high emissions scenario, neighborhoods with one or more at-risk facilities have higher proportions of renters, households in poverty, Hispanic residents, linguistically isolated households, households without vehicles, seniors and non-voters compared to neighborhoods without such facilities.
"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," Cushing said.
The methodology was developed with input from public health experts and community leaders in coastal areas.
Room for Action
Despite the grim projections, the authors note that moderate cuts to climate pollution could reduce the number of at-risk sites by more than 300 by the end of the century.
"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 Dr. Rachel Morello-Frosch of UC Berkeley's School of Public Health, a co-author of the study.
Morello-Frosch emphasized the need for policy action: "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."
California's Risk
California ranks fifth nationwide for sites at risk. In Los Angeles County, the South Bay region faces the heaviest impact due to its concentration of industrial and hazardous waste sites plus oil infrastructure near the coastline.
Cushing noted that aggressive greenhouse gas reduction remains critical for long-term risk reduction. She said investments in clean energy, pollution prevention and community resilience — along with regulatory changes requiring sea level rise consideration in remediation and emergency plans — could help mitigate contaminant releases during floods and natural disasters.
The researchers acknowledged limitations in their analysis, including potential errors in facility location databases and an inability to examine groundwater upwelling or factor in increasingly frequent and intense storms, which may mean actual risks are higher than projected.
The study was funded wholly or in part by the U.S. Environmental Protection Agency.