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What Does the Modern History of Flooding in the Delaware River Basin Say about Toxic Floodwater Threats in the Region?

Public Protections Chemicals

In a recent post, my colleague M. Isabelle Chaudry provided readers with an overview of some of the toxic chemical threats facing the Delaware River basin in the northeastern United States. In this post, I dig deeper into the modern history of flooding in a region that will be home to 9 million people by 2030 and how this poses a growing risk of toxic floodwaters for families and communities in Pennsylvania, Delaware, New Jersey, and New York.

During modern times, repeated floods have plagued the tributaries and main branch of the Delaware River, as well as its reservoirs. In just one example, a massive flood occurred in August 1955 when Hurricanes Connie and Diane dumped a total of 20 inches of water throughout the river basin in just one week. The flood killed 99 people and resulted in an estimated $2.8 billion in damages (in today’s dollars).

Some 50 years later, a string of floods hit the region in September 2004, April 2005, and June 2006. The most recent notable flood occurred in April 2022, when heavy rain caused the river to overrun its banks.

In response to the 2004-2006 floods, the Delaware River Basin Commission (DRBC) established the Delaware River Basin Interstate Flood Mitigation Task Force to recommend ways to prevent and relieve flooding impacts in the watershed. In 2007, the task force issued its final report and highlighted six focus areas for improvement: flood warnings, reservoir operations, floodplain regulations, floodplain mapping, structural and non-structural mitigation, and stormwater management.

While the final report was seemingly comprehensive, it missed a major flood-related hazard: toxic chemicals spilling and leaking from industrial sites and other facilities during and after a flood — a risk that continues to grow as our climate continues to warm.

Toxic floodwaters threaten the Delaware basin

Dozens of industrial sites line the main branch of the Delaware River, and hundreds are located throughout the river basin. Thousands of hazardous waste sites also populate the region. According to a 2018 fact sheet from the Public Interest Network, 126 of these locations are on the Superfund National Priorities List, which ranks the nation’s dangerous waste sites. A brief review of the U.S. Environmental Protection Agency’s Toxics Release Inventory (TRI) data indicates there may have been as many as 82 releases of pollutants into the river basin system in 2020 alone — and that only covers toxic pollution that companies reported to the agency under the TRI program.

A 2020 press release by the New Jersey chapter of the Sierra Club further highlighted the risks associated with industrial and hazardous waste sites in flood-prone areas. In many cases, Superfund sites are “capped,” meaning the contaminated soil is still located at the site but is contained and covered over. Generally, caps are safe as long as they are properly constructed and regularly maintained. However, they can erode, crack, or develop holes over time and allow contaminants to seep into groundwater. Flooding events can further undermine the integrity of the caps, causing cracks or holes, or floodwater can seep into cracks or holes that are already present in the cap, eventually carrying chemicals into floodwaters that can contaminate the environment, nearby communities, and individual homes and businesses.

Industrial facilities that produce, use, and store toxic materials on site can also pose a toxic flooding threat in the region. According to data pulled from the Pennsylvania Department of Environmental Protection (PADEP), there are 1,907 active registered aboveground and underground storage tanks in Philadelphia County alone, along with 9,908 inactive tanks, 45 percent of which are listed as “closed” and “permanently closed in place.” If storage tanks are improperly maintained, they can leak hazardous materials into the environment. Flooding may undermine the integrity of the tanks or facilitate the movement of hazardous materials into soil, surface water, and groundwater. 

Toxic floodwaters and environmental justice

Toxic chemicals that contaminate floodwaters harm both the environment and people living in a flooded area. Communities in the immediate areas surrounding industrial facilities are known as “fenceline communities.” A 2014 nationwide study of 3,433 facilities conducted by the Environmental Justice and Health Alliance for Chemical Policy Reform showed that Black people are 75 percent and Latinos are 60 percent more likely to live in fenceline communities compared to other Americans. Additionally, the poverty rate in these communities is 50 percent higher than the country as a whole. 

Pennsylvania’s environmental department defines “environmental justice areas” (EJ areas) as census tracts where at least 20 percent of the population are at or below the poverty line, or 30 percent or more of the population are people of color. A brief review of a map available on PADEP’s website indicates several EJ areas along the main branch of the Delaware River in Pennsylvania, including most of Philadelphia County, and parts of Bucks, Northampton, Monroe, and Pike counties.

While PADEP focuses on increasing participation and engagement in environmental decisions in these areas, it’s unclear what, if anything, the agency is doing to lower the risk of toxic flooding in these communities.

The disproportionate exposure of low-income communities and communities of color to the chemicals and hazardous materials released by industrial facilities, in the Delaware basin and beyond, already causes an increase in heart and lung diseases, as well as certain types of cancers. Exposure to toxic floodwaters can cause a myriad of health concerns, including rashes, headaches, and gastrointestinal illnesses. If a flood were to cause hazardous materials stored onsite at such facilities to enter the river or other parts of the watershed, these harms could increase exponentially and devastate fenceline, overburdened, and underserved communities.

Strict oversight and enforcement are needed to help address this issue:

  • The EPA and PADEP should ensure compliance with all current, relevant standards and regulations, such as the Clean Water Act and Pennsylvania’s Storage Tank and Spill Prevention Act.
  • There should be routine and diligent inspections of areas of concern, such as Superfund sites and storage tanks.
  • Long term, regulations should be enhanced to prevent industrial development in flood-prone areas and to reduce the amount of allowable pollutants discharged into the Delaware River.

Readers who wish to take an active role in this issue can consider several options:

  • Report concerns about hazardous spills and leaks to the appropriate agency, for example the EPA or PADEP.
  • Contact legislators and government officials, especially at the local and state levels, to voice support for stricter regulations, diligent enforcement, and encourage positive change.
  • Organize or participate in protests or petitions against harmful industrial development in local communities.
  • Utilize resources such as the Federal Register or Pennsylvania Bulletin to stay aware of proposed changes to rules and regulations governing industrial activity and water pollution and consider leaving a public comment sharing your thoughts on those changes.

Stay tuned to this space for more on protecting the Delaware River basin and other watersheds from the threat of toxic flooding, and be sure to follow us on social media and subscribe to our email list.

Public Protections Chemicals

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