Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

< Back to Toxic Tuesdays

From Risk Assessment to Presumption

The last several issues of this series in Toxic Tuesday have addressed the difficulty in interpreting health risks when people are exposed to toxic chemicals. The last issue focused on the failure of the risk assessment approach to address these difficulties and the many critical limitations which make it inadequate and inappropriate for assessing public health risks. 

Despite these limitations, the government still relies on the risk assessment model as the “go-to” method to determine if the health problems people are suffering are due to exposures occurring or suspected of occurring in a community. Risk assessment fails to answer the basic question that people ask when exposed to toxic chemicals: How will my health, or the health of my children or family, be affected by these chemicals?

What we have seen over the years is that risk assessment cannot answer this question, no matter how well done or how much context is provided to help reduce misuse and misunderstanding. People exposed to toxic chemicals live for years with their exposures as scientists do health studies, health assessments, evaluate data on exposures and try to estimate risks. In most cases, people are told that the risk assessment shows that the level of toxic chemicals that people were exposed to are not likely (or some similar caveat) to cause any adverse health effects. Consequently, little, if any action is taken to protect communities exposed to toxic chemicals.

As part of CHEJ’s Unequal Response Unequal Protection campaign, we have been working with community leaders and environmental health scientists to develop a new approach that centers community leadership to address the difficult questions about chemical exposures. Instead of trying to determine if the health problems reported in a community were directly caused by the specific exposures to toxic chemicals occurring in that community, we adopted the approach  used by the federal government when considering adverse health effects suffered by veterans, active military, first responders, 9/11 victims and others exposed to toxic chemicals while serving their country.

In these situations, the government recognized that critical scientific information linking exposures and health outcomes was missing or incomplete thus making it necessary to make “presumptions” about exposures leading to the health problems suffered by these groups. This recognition led to the government providing health care, treatment, compensation and other assistance needed due to exposure to toxic substances suffered while serving our country. In communities where people have been exposed to toxic chemicals through no fault of their own, the government would extend a similar application of the presumptive approach. 

The presumptive approach asks what scientific information is sufficient to take action to protect people exposed to toxic chemicals? We propose the following approach to answer this question.

  1. Using existing and newly generated environmental sampling results collected in the impacted area, government (or an expert team of scientists) would compile a list of toxic substances to which the community is exposed.
  1. An independent committee of environmental and public health experts would then review the literature and determine what adverse health effects/diseases are associated with the toxic chemical(s) identified. Exposure to a chemical will be presumed to cause an adverse health effect if the evidence linking the chemical and the health effect is at least as likely as not, based on the strength of the studies found. The diseases with a positive association to the toxic substances present in the community would be used to decide which diseases will be presumed to be associated with the chemicals identified in the community.

Based on results of this approach, appropriate action to safeguard the health of the community can be taken. This decision could include remedies to lessen exposures and lessen the risk of injury and the effects of exposure. They might also include evacuation, providing a clean water supply, closing a polluting facility or implementing new emissions limitations.

Learn about more toxics