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Toxic Tuesdays

1,4-dichlorobenzene (1,4-DCB)

Toxic Tuesdays

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

1,4-dichlorobenzene (1,4-DCB)

1,4-dichlorobenzene (1,4-DCB) – also known as p-dichlorobenzene (p-DCB) – is a colorless solid chemical that readily evaporates into the air. 1,4-DCB does not occur in nature, and it is often produced for use in deodorants or disinfectants because it has a strong odor that humans can smell at very low concentrations. It is commonly used in household products like mothballs and deodorizing sprays. It also has industrial uses as a pesticide ingredient and a precursor to commercial dyes. 1,4-DCB can enter the environment through its household uses, pesticides, and industrial waste disposal. 1,4-DCB mostly enters the environment as a vapor, and people are likely to inhale it in homes and buildings where it is used. Solid 1,4-DCB can also bind to soil and remain there for long periods of time, but people are less likely to be exposed to it in this way.

Inhaling high concentrations of 1,4-DCB can cause irritation or burning sensations in the eyes and nose. It can also cause coughing, nausea, difficulty breathing, dizziness, headaches, and liver dysfunction. Touching products that contain 1,4-DCB can also cause burning sensations on the skin. In studies of laboratory animals, 1,4-DCB exposure caused liver, kidney, and blood defects as well as liver cancer. The US Department of Health and Human Services and the International Agency for Research on Cancer both classify it as being reasonably anticipated to cause cancer.

Because of the danger to human health, the Environmental Protection Agency has set a maximum 1,4-DCB concentration that can be present in drinking water without observing adverse health effects. The European Union has gone even further, banning use of 1,4-DCB in mothballs and air fresheners because of its potential to cause cancer. Similar regulation in the US could protect more people from the health risks of 1,4-DCB exposure.

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Barium

Toxic Tuesdays

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

Barium

Barium is a silver-colored metal which is found in the earth in compounds with other elements. Many barium compounds have industrial uses: barium sulfate is used as a drilling lubricant by the oil and gas industries to facilitate drilling through rock; barium carbonate is a rat poison; and barium oxide is used in the production of electronics and glass. Barium can enter the air through the production of barium-containing compounds and the improper disposal of barium-containing waste. It can then enter the soil and water. Barium compounds that do not dissolve in water can persist in the soil and water for a long time.

People are most likely to be exposed to barium by drinking contaminated water. Barium compounds that do not dissolve in water – like barium sulfate and barium carbonate – are not known to be harmful to human health. However, barium compounds that do dissolve in water – like barium chloride and barium hydroxide – can harm human health because they release barium ions into the body. Barium ions interfere with the normal electrical impulses generated in the brain, muscles, and heart. Exposure can cause gastrointestinal dysfunction such as vomiting, diarrhea, and abdominal cramps. It can also cause anxiety, disorientation, difficulty breathing, decreased blood pressure, numbness, muscle weakness, and paralysis. The eyes, immune system, respiratory system, and skin can also be damaged by barium exposure. The Environmental Protection Agency (EPA) has set a limit on how much barium can safely be in drinking water, but almost 800 Superfund sites are known to have barium contamination, suggesting that there may be potential for barium exposure in some communities.

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What Scientists Know and Don’t Know About Exposures to Low Level Mixtures of Toxic Chemicals

Toxic Tuesdays

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

What Scientists Know and Don’t Know About Exposures to Low Level Mixtures of Toxic Chemicals

Not long ago, the Huffington Post ran a story called: A Roll of the Dice: The Unknown Threat of Exposures to Chemical Mixtures, by Chris D’Angelo that talked about the difficulties scientists are having in answering the questions about adverse health effects following the horrific train derailment in East Palestine, OH more than a year ago. It’s an important article for anyone dealing with a toxic chemical exposure issue, especially in a community setting. 

It’s important because it gets to the heart of the science – what scientists know and don’t know about low level multiple chemical exposures to toxic chemicals such as occurred in East Palestine and many other contaminated sites around the country. In most cases, people are exposed to multiple chemicals simultaneously at low concentrations over various periods of time. Rarely are people exposed to just one chemical.

Yet when the government steps in to assess the health risks at these sites, they use the best tool available to them – risk assessments based on peer reviewed published data. The article discusses why this approach is very limited in what it can tell about the risks people face from exposure to multiple chemicals at low concentrations. Risk assessment is limited because virtually all of the published peer reviewed data addresses exposure to only a single chemical at a time and that very little data exists to inform what happens when people are exposed to multiple chemicals at low concentrations. Linda Birnbaum, former director of the National Institute of Environmental Health Sciences, told D’Angelo that mixtures are a complex problem that has long frustrated the field of toxicology.

The risk assessment process relies on this limited scientific data because it’s all we have to assess health risks. D’Angelo points this out arguing that data derived from exposure to one chemical at a time bears no relationship to the actual risks people face in the real world such as in East Palestine. He describes it this way: “In communities like East Palestine, Ohio, where residents were exposed to potentially dozens of different chemicals following the fiery derailment of a Norfolk Southern train in February, environmental agencies are often quick to declare the air, water, and soil safe, despite having little grasp of how substances could be interacting to harm human health.”

D’Angelo points out that the “…dangers in East Palestine may not be any one chemical but several working in tandem. And the fields of toxicology and epidemiology remain largely incapable of investigating and understanding that threat.”

But instead of acknowledging what the science actually tells us about exposures to low level mixtures of toxic chemicals, government, in the case of East Palestine, has released disingenuous and misleading statements meant to reassure the public that everything is alright and taking no action to address the adverse health symptoms that the people in East Palestine are continuing to experience including nose bleeds, headaches, skin rashes and breathing difficulties.

If the EPA and other health agencies were honest and truthful with the public, they would tell the people of East Palestine that they really don’t know the true exposure risks, that scientists don’t know very much about what happens to people exposed to low level mixtures of toxic chemicals. While perhaps not reassuring, the truth allows everyone to better understand what’ they are facing.  

The article concludes with a way forward by suggesting that EPA should follow the lead of what the government did to take care of Vietnam Veterans who were exposed to Agent Orange and the soldiers exposed to emissions from the burn pits in Iraq and Afghanistan, among others. In these cases, soldiers do not have to prove that their illnesses were caused by their exposure to toxic chemicals. If they can show that they were exposed, that’s sufficient for them to get health care and other compensation.

Communities like East Palestine shouldn’t be held to a different standard, especially given the many unknowns about the toxic exposures caused by the train derailment. In the absence of a basic understanding of what adverse health effects might result from exposures to the mixtures of toxic chemicals released into the community by the train derailment, the government should take steps to move the people of East Palestine who want to move, provide health care for those who were exposed and establish a medical monitoring program to follow these people.

These steps will begin the long and difficult process of acknowledging what we know and don’t know about exposes to low level mixtures of toxic chemicals and begin to learn what happens to the people exposed in these situations. Read the full article here.

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Carbon Monoxide

Toxic Tuesdays

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

Carbon Monoxide

Carbon monoxide is a toxic gas that is difficult to detect because it has no smell, taste, or color. It can be produced from both natural and human-made sources when carbon fuel – such as gasoline, wood, coal, charcoal, propane, natural gas, or trash – is incompletely burned. The most common source of carbon monoxide in outdoor air is exhaust from gas-powered vehicles. It can also be produced in indoor air through house fires or use of gas-powered appliances such as portable generators, furnaces, water heaters, stoves, and fireplaces. Carbon monoxide is also produced in industrial chemical manufacturing to create a group of plastics called polycarbonates.

When carbon monoxide enters the air it can remain there for several months. Inhaling air contaminated with carbon monoxide interferes with red blood cells’ ability to carry oxygen throughout the body. This can cause difficulty with breathing, headache, nausea, dizziness, vomiting, vision impairment, confusion, and chest pain. In high doses it can cause seizures, coma, and death. Exposure to high doses while pregnant can also cause miscarriage. People with heart or lung diseases are particularly vulnerable to the effects of carbon monoxide exposure. Even once exposure to carbon monoxide has ended, there can be long-term effects on heart and brain function.

Because of the extreme toxicity of carbon monoxide, the Environmental Protection Agency (EPA) sets standards for safe levels of carbon monoxide in the air. Despite these standards, studies estimate that 50,000 people in the United States need emergency medical treatment for carbon monoxide exposure each year, and that about 1,000 die from carbon monoxide exposure each year. Carbon monoxide has also been found in many Superfund sites identified by the EPA. These realities indicate that more stringent standards, testing, and regulations may be necessary to keep people safe from carbon monoxide.

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Acrolein

Toxic Tuesdays

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

Acrolein

Acrolein is a toxic chemical that presents itself as a clear to yellowish liquid that evaporates quickly and is highly flammable. As it vaporizes, it has an unpleasant smell and tends to accumulate in low areas since it is heavier than air. Acrolein is used as a precursor ingredient in many different kinds of manufacturing industries including plastics, paint, leather finishings, and paper coatings. It is also used as a biocide to control plant and algae growth in water systems.

Acrolein exposure usually occurs in the form of inhalation. Acrolein is formed from the combustion of certain organic compounds. As such, it is commonly formed from the burning of fossil fuels, animal and vegetable fats, and tobacco. It is a common, albeit minimal, by-product of forest fires.

The health effects of short-term exposures to acrolein are fairly well understood. Acrolein is severely irritating to skin, eyes, and mucous membranes. If inhaled, it causes respiratory distress, an asthma-like reaction, and delayed pulmonary swelling. Contact with the skin or eyes produces irritation and lacrimation, and can result in chemical burns.

The long-term health effects of acrolein are much less studied. There are some indications that prolonged exposure can cause respiratory sensitization, a process through which exposure to a chemical leads to hypersensitivity of the airways when exposed again to the same or similar chemicals. Potential adverse reproductive effects or links to cancer have not been explored well enough to draw any conclusions.

It is perhaps this uncertainty over long-term health effects that most concerns residents of East Palestine, OH. After the train derailment dumped more than 1 million pounds of various industrial chemicals in the community, authorities responded by removing some of the contamination and performing controlled burns on the rest. These activities have released dangerous levels of acrolein into the air, as an analysis of EPA data by Texas A&M researchers revealed. Despite accurately assessing the immediate health impacts of acrolein on the community, it is a shame that the same researchers then downplayed the risks of prolonged exposure by saying that “it would take months, if not years, of exposure to the pollutants for serious health effects.” This is simply not true, as we have very little information about long-term exposure to even low levels of acrolein. The situation in East Palestine is extremely worrisome, and researchers downplaying the health risks the community is facing is very counterproductive to the situation.

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Trihalomethanes (THMs)

Toxic Tuesdays

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

Trihalomethanes (THMs)

Trihalomethanes (THMs) are a class of chemical compounds which contain three halogen atoms. Common THMs include chloroform, fluoroform, and chlorodifluoromethane. While THMs are used in some industrial processes like refrigeration, people are most likely to be exposed to them through drinking water. Most water utilities use small amounts of chlorine as a disinfectant to keep water supplies clean. While adding chlorine is generally accepted to be an important practice to protect public health, this chlorine can react with organic matter in the water and create THMs. Drinking contaminated water is generally considered to be the most serious route of exposure to THMs, though one study has found that bathing with contaminated water causes even higher exposure. THMs are odorless and flavorless, so people may not know if they have been exposed.

Many types of THMs have adverse health effects upon exposure, and there are four that are known to be particularly harmful to human health:

  1. Chloroform is known to cause lung, liver, and kidney damage, and in high doses can lead to death. In studies of laboratory animals, drinking chloroform-contaminated water caused liver and kidney cancer. The Environmental Protection Agency (EPA) classifies it as a likely cancer-causing agent in humans. 
  2. Bromoform can cause neurological impairments, unconsciousness, and death. In studies of laboratory animals, drinking bromoform-contaminated water caused liver and kidney cancer. EPA classifies it as a probable cancer-causing agent in humans.
  3. Dibromochloromethane is less well understood, but in studies of laboratory animals, drinking contaminated water caused liver and kidney cancer. EPA classifies it as a possible cancer-causing agent in humans.
  4. Bromodichloromethane is known to cause liver, kidney, and immune system damage. It can also cause reproductive system damage and lead to miscarriage and low birth weight. In studies of laboratory animals, drinking bromodichloromethane-contaminated water caused intestinal, kidney, and liver cancer. EPA classifies it as a probable cancer-causing agent in humans.

Because of the danger of THM exposure, EPA regulates the maximum amount of total THMs allowed in tap water. While this can help keep people safe, regulating the total THMs may not necessarily be effective because each type of THM can cause health effects on their own. Furthermore, little is known about the health effects of simultaneous exposure to multiple THMs. EPA has maximum contaminant level goals (MCLGs) for each of the four THMs listed above, but these goals are not enforced by laws or regulations, so they have no power to keep people safe. Because most people get their water from chlorinated municipal water supplies, and because THMs have such serious health effects, more must be done to keep people safe from exposure. This includes more studies to understand the effects of simultaneous exposure to multiple THMs and enforceable standards for individual THMs in drinking water.

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Cyanide

Toxic Tuesdays

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

Cyanide

Cyanide is a chemical usually found in compounds with other chemicals. Cyanide compounds can be found in some bacteria, fungi, algae, and the seeds of stone fruits. One of the most dangerous cyanide compounds is hydrogen cyanide, a colorless gas that smells like almonds. It is used in industrial processes such as electroplating, metallurgy, metal mining, plastics production, organic chemical production, and photographic developing. Hydrogen cyanide can enter the air surrounding industrial settings where it is used. It can also be produced by combustion engines, tobacco smoke, and the burning of acrylonitrile plastics. (CHEJ has previously written about acrylonitrile here). Because acrylonitrile is used in many consumer plastics, building fires are one of the most common ways people are exposed to hydrogen cyanide.

Breathing hydrogen cyanide for even short amounts of time is incredibly dangerous and can lead to death. When cyanide enters the body it stops cells from being able to produce energy, interfering with many life-sustaining functions of the brain and heart. Early symptoms of cyanide exposure occur within minutes and include headache, dizziness, elevated heart rate, shortness of breath, and vomiting. This can then progress to seizures, decreased heart rate, low blood pressure, coma, heart attack, and death. People who survive exposure can have lifelong neurological impairments. Factory workers who inhaled low levels of hydrogen cyanide over years have reported trouble breathing, chest pain, vomiting, and headaches. Exposure to other cyanide-containing compounds results in the same health effects. Because of the extreme toxicity of cyanide exposure, the use of cyanide-containing compounds and the use of compounds that can produce cyanide when burned should be restricted in order to protect public health.

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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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Glyphosate Risks

Toxic Tuesdays

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

Glyphosate Risks

Glyphosate is a chemical found in weed killer products like RoundUpTM used on farms and home lawns. Because of its effectiveness, glyphosate has become the most widely used herbicide in the world. People who work with these products and people who live near farms where they are used can get exposed to glyphosate through the air. The International Agency for Research on Cancer (IARC) has concluded that glyphosate exposure probably causes blood cancers. 81% of American adults and children have detectable concentrations of glyphosate in their urine. While much is still unknown about the potential health risks of glyphosate exposure, two recently published studies illuminate how big a concern it may be for both workers and the public.

One study aimed at assessing the potential cancer risk posed to farmers who work with glyphosate-containing herbicides. The study used data from the Agricultural Health Study (AHS), which collected biological samples from private and commercial pesticide applicators in Iowa and North Carolina from 1993-1997. The study analyzed AHS participants who were male, above the age of 50, had no blood disorders, and had not been diagnosed with cancer, which created a sample of 1,681 people. The researchers analyzed the DNA of these participants to look for the loss of large portions of DNA in the Y chromosome. Significant loss of DNA portions can have a massive effect on how the body’s cells function and have been linked to increased risk for cancer. Losses of large portions of DNA in the Y chromosome have been specifically linked to blood cancers like those that may be caused by glyphosate exposure.

In the study, 21% of participants had lost large portions of the DNA in their Y chromosome in some of their cells. Statistical analysis found that using glyphosate-containing pesticides for either a longer period or with more intensity were both associated with more DNA loss in the Y chromosome. While these findings do not prove that occupational exposure to glyphosate causes cancer, they provide important biological evidence that glyphosate exposure can cause the kinds of largescale changes in DNA that are associated with cancer. It is the first study of agricultural workers to show this association between glyphosate and DNA loss.

A second study sought the extent of glyphosate exposure among people who live near farms where glyphosate is used. Some studies have shown that glyphosate exposure during pregnancy is associated with reduced fetal growth and pre-term birth. Thus, this study focused on measuring glyphosate levels of pregnant people in Idaho who live near farms that use glyphosate. The study included 40 participants in Idaho who were in their first trimester of pregnancy in 2021. Researchers collected weekly urine samples from participants until delivery. Half of participants lived near farms (less than 0.5 kilometers from a farm) and half lived far from farms (more than 0.5 kilometers from a farm). About two-thirds of both groups had detectable concentrations of glyphosate in their urine.

For participants living near farms, the frequency and concentration of glyphosate detection in urine increased significantly during the pesticide spray season (from May to August) compared to the non-spray season. This change did not occur in participants living far from farms, indicating that increased exposure to glyphosate was likely a result of pesticide spraying. While these findings do not directly track the health effects on pregnant participants or their infants, it is important biological evidence that agricultural use of glyphosate exposes nearby residents. It is the first study to demonstrate that residential proximity to farms using glyphosate is associated with increased glyphosate in the body.

These two studies demonstrate that glyphosate may pose risks to both workers and the public. CHEJ has previously written about the uses and health risks of glyphosate here.

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Thallium

Toxic Tuesdays

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

Thallium

Thallium is a metal found in the Earth’s crust and can be obtained by smelting metal compounds. Today, most thallium is used in the production of electronics, especially semiconductors. It is also used for medical imaging and in the production of glass. Thallium contamination of the surrounding environment most commonly results from the smelting process, but it can also happen during transport or improper disposal. Once in the environment, it remains in the air, water, and soil without breaking down. It can enter the food chain because it is absorbed by plants and builds up in fish.

Eating food contaminated with thallium is the most likely way people in the United States would be exposed to it. Ingesting high levels of thallium over a short period of time can lead to symptoms such as vomiting, diarrhea, and hair loss. It can impair function of the brain, lungs, heart, liver, kidneys, and even lead to death. Little is known about the health effects of ingesting low levels of thallium over a long period of time. People who work in facilities that use thallium or live near waste sites containing thallium can also be exposed by breathing contaminated air or touching contaminated material. Workers exposed to thallium over many years have had nervous system impairments, including numbness in the extremities. Studies on laboratory animals have shown that exposure to high levels of thallium can cause reproductive and developmental defects, but it is not known if this also occurs in people.

Historically, thallium was a common ingredient in rat poisons and insecticides sold in the United States. Recognizing that it is highly toxic, the government banned its use in these consumer products in 1972. In fact, thallium is considered so dangerous that it is no longer produced in the United States. Many other countries also ban or restrict the production of thallium. While these are positive developments to keep people safe, at lease 210 Superfund sites are known to contain thallium, meaning it still poses a danger to people’s health today.

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