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Toxic Tuesdays

Acknowledging the Limits to Assessing Low Dose Mixtures of Toxic Chemicals​

Toxic Tuesdays

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

Acknowledging the Limits to Assessing Low Dose Mixtures of Toxic Chemicals

Approximately 1 year ago a Norfolk Southern train carrying more than 150 cars, many of which containing toxic chemicals derailed in East Palestine, OH. Thirty-eight of the train cars derailed and a decision was made by Norfolk Southern to burn the contents of 5 tanker cars containing vinyl chloride and other toxic chemicals. This unleashed a huge black cloud of particulates that enveloped the surrounding neighborhoods and farms in both OH and PA.

Immediately after the burn, people in East Palestine began reporting adverse health symptoms including, headaches, nose bleeds, skin rashes, central nervous symptoms, thyroid problems and more. These and other adverse health problems have continued to plague the residents of this rural midwestern town.

EPA responded immediately by telling people that everything was alright, that there was no cause for alarm. EPA’s testing found no levels of “concern.” But the people in East Palestine could not accept this narrative because they knew things were not right. They knew the health effects they were suffering were real. They knew that EPA was not telling them the truth.

If EPA were honest with the people at East Palestine, they would have told them that they don’t understand why people are continuing to report so many illnesses while their data tells them that there should not be any adverse health problems in the community.

But if EPA did that, if they acknowledged how little is known about the link between adverse health effects and exposures to mixtures of chemicals, the people of East Palestine would demand action in the face of these uncertainties. Action like paying for people to relocate from the area so that they can stop being exposed to the toxic chemicals which are still in the air, getting the health care they need and moving on with lives.

It is clear from the situation in East Palestine that very little is known about how people respond to exposures to low level mixtures of toxic chemicals. It’s time to acknowledge that the scientific understanding does not exist to explain what is happening to the health of the people in East Palestine or other communities exposed to toxic chemicals. It’s time to recognize that we cannot rely on traditional toxicology to answer the questions people have about their exposures to low level chemical mixtures.

In an editorial about evaluating low dose exposures, Linda Birnbaum, former director of the National Institute for Environmental Health Sciences, described the traditional approach to evaluating health risks as “antiquated” and said that it needs to be replaced by a “better understanding of the actual characteristics of modern environmental chemicals.” Birnbaum went on to say that “It is time to start the conversation between environmental health scientists, toxicologists, and risk assessors to determine how our understanding of low doses effects and non-monotonic dose responses influence the way risk assessments are performed for chemicals with endocrine disrupting activities.”

It’s time to acknowledge that the tools we have are not able to answer the questions people ask about their exposures to toxic chemicals and give people the relief they are asking or, whether it’s cleanup, relocation, health care or something else.   

This is exactly what the government did for the Vietnam veterans exposed to Agent Orange; for the atomic bomb victims exposed to radiation fallout; for the 9/11 first responders in New York City; for the soldiers exposed to burn-pit smoke in Iraq and Afghanistan; and for the marines and their families at Camp Lejeune, North Carolina who drank contaminated water.

In each of these instances, the government recognized that the science linking exposure and health outcomes was impossible to assess and instead of requiring proof of cause and effect, they said, enough, we need to take care of our own and moved to a presumptive scientific approach that allowed veterans and first responders to get health care and other compensation. We should do the same for the people of East Palestine and in hundreds of other communities that have been exposed to low level mixtures of toxic chemicals.

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It’s Time to Do Right by the People in East Palestine, OH – and Elsewhere

Photo credit: CNN

By Stephen Lester.

Nearly 10 months ago, a Norfolk Southern train with more than 150 cars, many of which contained toxic chemicals, derailed in East Palestine, OH. Thirty-eight of the train cars derailed and a decision was made by Norfolk Southern to burn the contents of 5 tanker cars containing vinyl chloride and other toxic chemicals. This unleashed a huge black cloud full of particulates that enveloped the surrounding neighborhoods and farms in both OH and PA.

Immediately after the burn, people in East Palestine began reporting adverse health symptoms including headaches, nose bleeds, skin rashes, central nervous symptoms, thyroid problems and more. These and other adverse health problems have continued to plague the residents of this rural midwestern town.

EPA immediately responded by telling people that everything was alright and there was no cause for alarm. EPA’s testing found no levels of “concern.” But the people in East Palestine could not accept this narrative because they knew things were not right. They knew the health effects they were suffering from were real. They knew that EPA was not telling them the truth.

If EPA were honest with the people at East Palestine, they would have told them that they didn’t understand why people were continuing to report so many illnesses while their data told them otherwise. But if EPA did acknowledge how little is known about the link between adverse health effects and exposures to mixtures of chemicals, the people of East Palestine would demand action in the face of these uncertainties. Actions like paying for relocations so that they can stop being exposed to the toxic chemicals that are still in the air and getting the health care they need to move on with their lives.

The people in East Palestine deserve better. So do hundreds of other communities across this country where people have similarly been exposed to low levels mixtures of toxic chemicals. It is clear from the situation in East Palestine that very little is known about how people respond to chemical exposures, especially to low level mixtures. This is evident when the EPA and other public health agencies who rely on traditional toxicology and risk assessment are telling the people of East Palestine that everything is safe when it clearly is not.

It’s time to acknowledge that the scientific understanding does not exist to explain what is happening to the health of the people in East Palestine. It’s time to recognize that we cannot rely on traditional toxicology to answer the questions people have about their exposures to low level chemical mixtures. It’s time to do the right thing by the people in East Palestine and by hundreds of communities across the U.S. where people are being exposed to low level mixtures of toxic chemicals. It’s time to acknowledge that the tools we have are not able to answer the questions people raise about their exposure to toxic chemicals and give people the relief they are asking for, whether it’s cleanup, relocation, health care or something else.   

It’s what the government did for the Vietnam veterans exposed to Agent Orange; for the atomic bomb victims exposed to radiation fallout; for the 9/11 first responders in New York City; for the soldiers exposed to burn-pit smoke in Iran and Afghanistan and other overseas locations; and for the Marines at Camp Lejeune, North Carolina who drank contaminated water. Do the people of East Palestine deserve anything less than the soldiers and first responders who protect this country?

In each of these instances, the government recognized that the science linking exposure and health outcomes was incomplete and instead of requiring proof of cause and effect, they said, “Enough, we will take care of our own.” They moved to a presumptive scientific approach that allowed veterans and first responders to  health care and other compensation. We should do the same for the people of East Palestine and in hundreds of other communities that have been exposed to low level mixtures of toxic chemicals.

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Chemical Mixtures May Lead to Cancer

A recently published scientific paper came to a striking conclusion – “the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies.” In other words, exposure to multiple chemicals at low doses, considered individually to be”safe could result in various low dose effects that lead to the formation of cancer. This is a remarkable observation and conclusion. It is also an important advance in the understanding of the risks chemicals pose to society.

Organized by the non-profit Getting to Know Cancer, a group of 350 cancer research scientists came together in Halifax, Nova Scotia in 2013 to address the question of continuous multiple chemical exposures and the risks these exposure pose. Referred to as the Halifax Project, this effort merged two very distinct fields – environmental toxicology and the biological mechanisms of cancer – and provided the opportunity for researchers to look at the diversity of environmental factors that contribute to cancer by examining the impact that exposure to very small amounts of chemicals can have on various systems of the body.

A task force of nearly 200 scientists formed at this meeting took on the challenge of assessing whether or not everyday exposures to mixtures of commonly encountered chemicals have a role to play in cancer causation. The researchers began by identifying a number of specific key pathways and mechanisms that are important in the formation of cancer. Then they identified individual (non-carcinogenic) chemicals that are commonly found in the environment that had some potential to disrupt these systems. A total of 85 environmental chemicals were identified.

The authors found that 59% of these chemicals (50/85) had low dose effects “at levels that are deemed relevant given the background levels of exposure that exist in the environment.” They found that only 15% of the chemicals reviewed (13/85) had a dose-response threshold and that the remaining 26% (22/85) could not be categorized due to a lack of dose-response information. The authors concluded that these results help “to validate the idea that chemicals can act disruptively on key cancer-related mechanisms at environmentally relevant levels of exposure.”

This is an incredibly important observation because it challenges the traditional thinking about how cancer forms in the body. It challenges the notion that all cancers share common traits (considered the “hallmarks of cancer”) that govern the transformation of normal cells to cancer cells. The authors also discuss how the results in this paper impact the process of risk assessment which even its most sophisticated model fails to address continuous exposures to mixtures of common chemicals.

The authors point out how surprisingly little is actually known about the combined effects of chemical mixtures on cancer related mechanisms and processes. This effort however seems to be a very positive step forward.

To read the full paper, go to <http://carcin.oxfordjournals.org/content/36/Suppl_1/S254.full.pdf+html>.