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A New Cumulative Impacts Website - May 2011

The Networker
I. A New Cumulative Impacts Website Nancy Myers


  I. A New Cumulative Impacts Website TOP

 by Nancy Myers

A new national project is addressing the problem of cumulative impacts, which cuts across ecosystem health, individual health, and environmental justice in communities. Emerging solutions represent the future of environmental policy.

"Cumulative impacts" refers to the cumulative effect of numerous adverse impacts on public health or ecosystems from environmental hazards. Where human communities are concerned, analyses must also take into account other factors such as age or poverty that increase vulnerability. It is the standard policy term for real-world complexity: multiple stresses, combining and accumulating, with harmful but often unpredictable outcomes.

The growing realization, after 50 years of environmental regulation, is that environmental problems cannot be managed simply chemical by chemical, river by river, and permit by permit. But current legal systems allow for little else. Work has begun in both government and nongovernment circles to build new foundations for environmental law and policy that will address cumulative impacts.

With this issue of the Networker, the Science and Environmental Health Network and the Collaborative on Health and the Environment are pleased to introduce a new website focused on cumulative impacts, The site assembles the latest science, emerging best practices, analytical tools, and legal shifts that can reduce cumulative harm to the planet, communities, and people.

The site is a centerpiece of a broad collaboration to confront the complex set of problems known as cumulative impacts. An advisory group includes several staff members of the US EPA and state environmental agencies as well as community and environmental activists, scientists, and scholars.

The Cumulative Impacts Project web-based library assembles:

  • The emerging science of evaluating cumulative impacts;
  • Model and emerging law and regulatory policies focused on containing and reducing cumulative impacts;
  • Best practices addressing cumulative impacts in communities including crosscutting solutions to multifactorial influences on health;
  • Case studies of preventive strategies for multifactorial diseases that may share common biological pathways as well as common environmental and social causes.

The site features a unique search system that encourages topical as well as keyword searches. For those who may be new to the issues, such as journalists and students, it is meant to facilitate self-education on the range of topics related to cumulative impacts. For those who are already deeply involved in advocacy and policy development it will serve as a convenient clearinghouse of relevant documents, links, and resources.

Big problems with few policy solutions

A year ago, project organizers worried that the term "cumulative impacts" was both cumbersome and obscure. But it crops up increasingly in news stories as well as journal articles and policy circles. Community activists use the term freely.

"Neighbors say the state doesn't take into account the cumulative effects of the soot and chemicals released from all the plants in the area," writes a Detroit journalistA Seattle reporter notes that the EPA "is still grappling with how to reconcile the increasing community demands for comprehensive cumulative 'impacts analysis' with the EPA's statutory constraints."

Nor is the concept controversial. Understanding the complexities of cumulative effects is hugely challenging, and the science of complex systems (including human bodies) is constantly evolving. However, the fact that multiple stresses combine and accumulate, with harmful but often unpredictable results, is not disputed. The real challenge is to develop policies that address that reality—making decisions when the stakes for health and survival are high but exact future outcomes are uncertain. That is the goal of the Cumulative Impacts Project.

Current decision-making structures are ill equipped to deal with cumulative impacts. With few exceptions, the risk management system incorporated into most environmental laws and agency decisions analyzes and controls each impact separately from all others. Generally, this system weighs the costs and benefits of each proposed remedy as though each impact occurred in isolation.

For example, health risks from exposure to specific toxic chemicals and industrial emissions are usually estimated separately, nutrition is not understood in the context of poverty, water quality is seen as separate from air quality, and so forth. But this system works poorly in the real world, when, for instance, a community is already suffering from poverty, unhealthy food, several polluting facilities, and lack of access to healthcare--or when total cumulative pollution from numerous sources exceeds a threshold for damaging human health or the environment, as in the case of global warming. Our current law makes it nearly impossible to consider the overburdened, cumulative context when each individual source of damage is evaluated, for instance, when another polluter requests an operating permit.

The emerging approach to climate change does provide a different approach. While any one source of carbon emissions would cause virtually no impact on the climate, the total cumulative impact of all such "harmless" emissions can alter the entire earth's climate. In this case it is clear that we must contain and reduce our total emissions rather than simply evaluate the costs and benefits of individual impacts. This kind of systems thinking about cumulative impacts needs to be applied to most of today's environmental health problems, so many of which arise as the result of cumulative impacts.

Cumulative impacts across the board

Although SEHN has been working on cumulative impacts science and law for a number of years (see, for example, the September 2009 Networker and the March 2011 Networker), this project began last year when we talked to activists, scientists, and policymakers about the need for a concerted effort to develop basic new policy approaches to cumulative impacts. We concluded the problem of cumulative impacts has three interrelated dimensions:

  • The individual and public health dimension: the interaction and cumulative impact of multiple factors in human disease;
  • The environmental justice dimension: the unfair distribution among communities of cumulative impacts of multiple environmental and socioeconomic stressors;
  • The ecosystem dimension: the cumulative impact of human activities, the human footprint, on ecosystems and the planet--the problem of the overburdened world.

We believe the reality of cumulative impacts is the ultimate and most urgent reason to base our decisions on the precautionary principle, which calls for preventing harm rather than only measuring and managing risk. The precautionary principle operates in the real world of scientific uncertainty: "When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically." (SEHN 1998 Wingspread Statement on the Precautionary Principle)

Human health

The Collaborative on Health and the Environment points out that chronic diseases and disabilities have reached epidemic proportions in the United States, affecting more than a third of the population. Asthma, autism, birth defects, cancers, developmental disabilities, diabetes, endometriosis, infertility, dementia, and other diseases and disabilities are causing increased suffering and concern. These diseases and conditions have several things in common:

  • Causation is usually complex, involving multiple factors.
  • Scientific evidence increasingly indicates that a number of environmental factors—including synthetic chemicals and pollutants as well as diet and socioeconomic conditions—are among the causal factors.
  • A number of these diseases share common physiological pathways and mechanisms (such as oxidative stress and inflammation), which are driven by some of the same human activities responsible for environmental degradation (such as industrial agriculture, air pollution). This suggests that we can find crosscutting solutions that will both prevent disease and benefit the natural environment.


Low-income communities and communities of color often bear a disproportionate burden of health risks from both environmental contamination and the stressful conditions that make individuals more vulnerable to illness. Members of these communities, like this woman from Ohio, frequently come to SEHN for help:

After a great deal of pressure from citizens we have just today received a summary of the cancer incidence data for [our community]. As a layman I see at least two possible clusters (2X national rate). The local citizens are taking this information to their local board of health to ask them to come up with a plan to reduce the cancer in their community. Is it possible for the board of health to contact you to get your opinion on this data?

In this case, as in many others, possible causes for the cancers may be too numerous for one-to-one links: a local hazardous waste incinerator and other polluting facilities, along with high natural radon levels. Clearly, reducing the cumulative impacts of these stressors is even more important than teasing out specific causes.

The US EPA is beginning to follow through on its longstanding calls for methods to analyze cumulative stressors to particular communities in order to address environmental justice. It has also issued calls for ways to address cumulative risks of chemical exposures in daily life. An important 2009 National Academy of Sciences study, Science and Decisions: Advancing Risk Assessment (pdf), recommends significant policy shifts including cumulative risk assessments, identifying hazards early, and seeking alternatives, which are ripe for implementation in agency decision processes.

As we established this project, several US EPA staff members and state agency representatives, along with environmental justice activists, enthusiastically agreed to join a working group on cumulative impacts. The agency members expressed support and gratitude for this project, which offers an opportunity for scientific and legal collaboration with a larger group and enhances government efforts that are often limited by political, bureaucratic, and budgetary constraints.


In the ecological sphere, the requirement to conduct "cumulative impact assessments" of proposed development and resource-extraction projects has been on the books for decades, as part of the National Environmental Policy Act. The Council on Environmental Quality issued guidelines (pdf) for conducting cumulative impact assessments in 1997. These call for evaluating cumulative impacts as background for whether or not to approve a particular proposed project--not, as we advocate, for broadly managing excessive cumulative impacts in a region, including both existing facilities and any proposed new projects. However, even this limited requirement has seldom been carried out.

Nevertheless, citizen groups are now becoming aware of increased potential for this enforcement tool that lies embedded in the law. For example, "cumulative impacts" has become a watchword around the boom in natural gas drilling involving hydrological fracturing or "fracking."

Dr. Sandra Steingraber, an ecologist, author, activist, and SEHN board member, told us recently that the Cumulative Impacts Project was especially timely for New York State, where "the focus of anti-fracking resistance is directed at the failure of the current state draft environmental impact statement to include cumulative impacts." She notes that 77,000 wells are likely, but the statement considers only effects from single well, and human health effects are not part of the study at all.

Enforcing existing rules on ecological cumulative impact assessments can provide models and precedents—or cautions—for developing similar procedures in the spheres of human health and communities. However, the real need in this sphere, as in the others, is not only to assess but to develop policies, technical tools, and legal decision-making structures designed to reduce cumulative impacts.

This project cuts a wide swathe. However, these three dimensions—human health, communities, and ecosystems—not only overlap but also call for common approaches, including

  • New legal and policy decision-making strategies;
  • Science relevant to understanding and addressing cumulative impacts;
  • Critiques of inadequate science;
  • Critiques of current laws and their inability to account for cumulative impacts;
  • Extensive experiments in developing new strategies, solutions, and best practices.

Emerging experiments

As California and a few other states and municipalities have begun to address the health impacts of disproportionate cumulative stressors on communities, SEHN has been part of these efforts. After two years of intensive work on the part of the CalEPA Cumulative Impacts and Precautionary Approaches Workgroup, of which SEHN Legal Director Joe Guth is a member, CalEPA issued a report in December 2010 outlining the first-ever strategy for comparing cumulative impacts on communities. The next step for the workgroup is to help develop "precautionary approaches"—guidance on legal decision-making structures that will actually reduce cumulative impacts, not just assess them. This is an even more challenging task.

These efforts have placed California at the forefront of developing the necessary experiments in addressing cumulative impacts. Also at this frontier is New Jersey, where SEHN board member Peter Montague is working on municipal policies that would reduce cumulative impacts and health disparities. Another emerging experiment is in a Minneapolis community, where organizers succeeded in obtaining a 2008 state law requiring the Minnesota Pollution Control Agency to analyze and consider "cumulative levels and effects of past and current pollution" before a permit may be issued for a facility located there.

Our experience suggests that tools can be developed to deal with cumulative impacts that address complexity and avoid the trap of "paralysis-by-analysis." SEHN and CHE's work on environmental health and the precautionary principle suggests:

  • Methods for precautionary decision-making that establish presumptions based on the inherent uncertainty and unexpected changes that we face;
  • Key shifts in the law including establishing the goal of containing and reducing cumulative impacts, such as in current proposals to curb climate change; placing the burden of proof on economic actors; and focusing on alternatives assessments rather than cost-benefit justifications of individual actions;
  • Crosscutting policy solutions that enhance both human and environmental health in communities, given that health and resilience are as intricately interwoven as disease and system failure. The solutions to cumulative impacts, especially in communities, do not lie solely in regulatory policy but also in planning and strategies that are both far-sighted and broad-sighted, addressing many problems at once. Often these strategies are deceptively simple—food access, green space, bike paths—but have powerful influences on the health of people, communities, and ecosystems.

We believe we can identify key intervention points and develop these new tools and policies. Information and the exchange of ideas are of key importance. This is a national project with many state and local experiments and connections. Until now the work on cumulative impacts has been conducted in isolation in diverse policy spheres and at different levels of jurisdiction. The purpose of this project is to promote the evolution of new policy at all levels through lively conversation, information exchange, and crossfertilization of ideas.

Monthly conference calls of a core working group began in February 2011. As the calls become primarily topical rather than focused on logistics, they will be open and widely announced through other listservs. Recordings will be posted on the website.

A related CHE Partnership call, "Cumulative impacts on health: New community-based research projects," is scheduled for June 9. It will feature reports from seven US EPA-funded researchers who are working with poor and underserved communities to determine how multiple stressors undermine their health as well as what interventions could be implemented to create healthier, more resilient communities.

Contact the project organizers at to join the cumulative impacts listserv, suggest resources for the website, and make inquiries.

Nancy Myers, SEHN communications director, oversees the Cumulative Impacts Project website.