Toxic Tuesdays

1,3-butadiene is a gas made from petroleum and is used to manufacture materials like synthetic rubber and plastics. Because it is a gas, 1,3-butadiene can easily leak out of production, storage, or disposal containers and enter the air. People who work in or live near facilities using 1,3-butadiene are most at risk of inhaling it, but even people in heavily polluted cities breathe air with 1,3-butadiene in it. Exposure to 1,3-butadiene can cause cardiovascular, neurological, lung, and blood defects. It is also suspected to cause birth defects and decreased birth weight. The Environmental Protection Agency, Department of Health and Human Services, and International Agency for Research on Cancer have all determined that 1,3-butadiene causes cancer. Studies of people who worked in facilities using 1,3-butadiene found that they had increased incidence of blood and immune system cancers compared to the general population.

1,4-dioxane is a clear liquid used in chemical manufacturing for industrial, consumer, and military purposes. During manufacturing or improper waste disposal 1,4-dioxane can be released into the environment. While it breaks down in air and doesn’t stick to soil, 1,4-dioxane is stable in water and can remain there for a long time. It can even accumulate in fish and plants that live in contaminated water. Eating these contaminated foods and drinking contaminated water are common ways people are exposed to 1,4-dioxane. Bathing in contaminated water can also cause 1,4-dioxane to evaporate into the air and be inhaled. Through its use in the manufacturing process, 1,4-dioxane often ends up being present in trace amounts in consumer products such as detergents, shampoos, and cosmetics. 1,4-dioxane present in these products can be absorbed through the skin.

2-Butanone is an industrial chemical that is also known as methyl ethyl ketone (MEK). It manifests itself as a colorless liquid under standard conditions, tends to evaporate into the air (volatize) quickly, and is quite flammable. 2-Butanone is manufactured in large amounts for use in paints, glues, and other finishes because of its properties as a strong solvent and because of how quickly it can evaporate. It is also released into the air from the combustion process of vehicles.

Arsenic is a naturally-occurring element found throughout the Earth’s crust. It is usually found combined with other elements creating a powder that is odorless and tasteless and can exist either in an organic or inorganic form. Inorganic arsenic compounds are highly toxic and for years were used to preserve wood. Copper chromated arsenate (CCA) was used to make “pressure-treated” lumber. Though no longer used for residential uses, CCA is still used in industrial applications. Organic arsenic compounds are used as pesticides, primarily on cotton fields and orchards.

It’s the Christmas season, and because real pine trees can be cumbersome and high maintenance, many families use artificial Christmas trees. While artificial trees seem like an easy and sustainable alternative, the materials they are made out of can pose health risks. Like many consumer products, artificial trees are often made with a type of plastic called polyvinyl chloride (PVC). PVC releases gases into the air that can cause dizziness and irritation to the eyes, nose, and lungs.

Asbestos is a group of fibrous minerals that can be found in the environment. The fibers of these minerals are strong, flexible, and heat-resistant, making them useful when spun or woven into sheets. Asbestos was used in building materials, heat-resistant products, and machinery components. When these products break down, asbestos particles enter the air and water. This means people who work in industries such as housing repair or demolition that disturb asbestos-containing materials are at high risk for exposure. People who live near such industries are also at risk.

Atrazine is one of the most common herbicides used in the United States, with over 70 million pounds applied to crops each year. Used mostly in large scale agriculture of crops such as corn, sugarcane, and pineapples, atrazine is the most widely detected herbicide in drinking water. Figures vary, but a conservative estimate puts measurable levels of atrazine in the drinking water of nearly 30 million Americans in 28 states. With so many people exposed to this compound, it is worth examining any potential effects it may have on people.

Benzene is a colorless chemical with a sweet odor that is flammable and presents itself in liquid form at normal temperatures and pressures. It is part of a family of chemicals commonly referred to as volatile organic compounds (VOCs), mainly because they evaporate quickly when exposed to air. Although benzene can be formed and emitted from natural processes, exposure to it comes mostly from human activities. Benzene is among the 20 most widely used chemicals in the United States. It is used as an industrial chemical in the production of a myriad of products including plastics, resins, synthetic fibers, rubber lubricants, dyes, detergents, drugs, and pesticides. Benzene is also naturally found in crude oil and is a major part of gasoline.

Benzo(a)pyrene (BaP) is a compound in a group of chemicals called polycyclic aromatic hydrocarbons (PAHs). PAHs like BaP are formed in the incomplete burning of coal, oil, gas, or other organic matter. Once formed, they can enter the air, water and soil. The most common way people are exposed to PAHs is by inhaling contaminated air. Vehicle exhaust, wood smoke, asphalt paving and agricultural burning can expose people to PAHs like BaP.

BPA stands for Bisphenol A and is a man-made chemical produced in large quantities for use primarily in the production of polycarbonate plastics. It is found in a large number of everyday products such as eyewear, water bottles, and epoxy resins that coat some metal food cans, bottle tops, and water supply pipes. BPA is a concerning chemical because it is one of those compounds that is in almost everything we use or come in contact with. The National Health and Nutrition Examination Survey (NHANES III) conducted by the Centers for Disease Control and Prevention (CDC) between 2003 and 2004 found detectable levels of BPA in 93% of people sampled six years and older.

Cadmium is a heavy metal found naturally in the earth’s crust. It is usually found as a mineral combined with other elements such as oxygen, chlorine, or sulfur. Cadmium is used in many industries and is essential in the production of batteries, certain alloys, coatings, solar cells, plastic stabilizers, and pigments. It is also found in significant quantities in cigarette smoke.

Chromium is a metal element found in rock. A common form is called hexavalent chromium, used in manufacturing settings for textile dyeing, wood preservation, and metal plating. Through release and disposal of waste from these facilities, hexavalent chromium can end up in the surrounding water and soil. People can then be exposed to it through drinking contaminated water, breathing in contaminated particles, or skin contact with contaminated materials.

The dose makes the poison is the most basic principle of toxicology. The first chapter in every toxicology textbook discusses how the response to a poison depends on how much of the poison you are exposed to (often referred to as the “dose”). This principle assumes that chemicals act by overwhelming the body’s defenses at higher doses. It also assumes that at some lower dose, there is no harm or no effect. But this basic principle may no longer hold true as what we know about exposures to toxic chemicals is changing.

Creosote is a large mixture of chemicals that is used as a wood preservative in the United States, as well as for roofing, aluminum smelting, and road paving. Houston’s Fifth Ward has been pinpointed as a Cancer Cluster: an area that has a “greater than expected number of cancer cases,” largely due to the community’s exposure to creosote from the Union Pacific railroad site in Houston’s 5th Ward.

Dioxins are a group of toxic compounds that share similar and distinct chemical structures. They are mainly byproducts of industrial processes, such as waste incineration. In 1979, the EPA banned products containing Polychlorinated Bihphenyls (PCBs), which is a chemical included under the term dioxin. However, dioxins were a major issue before the US began implementing regulations. Since dioxins break down extremely slowly, toxins that were released long ago are still being released into the environment.

Dioxins are a group of chemically related compounds formed as a byproduct of industrial processes such as water treatment, paper manufacturing, and waste incineration. If dioxins are not properly captured and stored, they can be released into the environment. Once released into the air, dioxins can travel thousands of miles. They can also attach to soil particles on the ground and sediment in bodies of water. Because dioxins are slow to decompose, they can persist in the environment for years after being released. One of the reasons this is a problem is because dioxins bioaccumulate in animal tissues, meaning if fish or livestock become exposed to dioxins, they accumulate in the animals. Then, when humans eat these contaminated animal products, we can be exposed to high levels of dioxins. This makes dioxins in food a particularly dangerous and widespread method of dioxin exposure.

The way scientists think about how chemicals cause their toxic effects is changing. Recent scientific research tells us that the traditional notion of how chemicals act is being replaced by a better understanding of the actual features of exposures that influence how chemicals express their adverse effects in people. These features include the timing and vulnerability of exposures, exposures to mixtures, effects at low doses and genetic alterations called epigenetics.

Ethylbenzene is a colorless flammable liquid that comes from coal tar and petroleum. It is primarily used to synthesize chemicals that are used in plastics. Ethylbenzene can also be used in fuels and injection fluid, which is used to release natural gas from the ground. It has industrial uses in solvents and pesticides and can also be found in consumer products like paint and ink.

Ethylene Oxide (EtO) is a colorless gas with a slightly sweet odor. It is used in making a variety of products including antifreeze, plastics, detergents, and adhesives. It is also used as a sterilizer for medical equipment and others that cannot be sterilized by steam. Ethylene Oxide can be found in the air surrounding industrial factories including chemical manufacturers and sterilizers.

Considering cumulative exposures to low levels mixtures of chemicals is an enormous challenge when evaluating the toxicity of chemicals. Neither the EPA nor ATSDR have guidance on how to evaluate exposure to multiple chemicals simultaneously, or cumulatively over time. The EPA does have its Risk-based Screening Levels (RSLs) that provide some guidance on risk estimates, but these values only consider chemicals in isolation, or when exposed to one chemical at a time. This limitation has begun to be recognized as a fundamental weakness in the way research is done on the toxicity of chemicals. Testing one chemical at a time is not sufficient nor appropriate for evaluating public health risks when people are exposed to multiple chemicals at the same time, or cumulatively over time.

Massive flooding in the state of Kentucky in late July 2022 claimed the lives of 38 people – yet another example of extreme weather events driven by the indiscriminate burning of fossil fuels. We touched upon this broad issue in a previous Toxic Tuesday about the wildfires that scorched the state of California not long ago. This edition will analyze the problem of massive flooding from the perspective of toxics.

Formaldehyde is a dangerous chemical that affects the respiratory system, lungs, eyes, and skin. It is classified as a carcinogen, hazardous substance, and hazardous waste. According to the American Cancer Society, Formaldehyde is a colorless, strong smelling gas used in making building materials and many common household products. It is well known for its preservative and anti-bacterial properties. It is commonly used in building materials such as particle board, pressed wood, insulation, glues and adhesives and more. It is also found in medicines, cosmetics, and cleaning products. Formaldehyde is even used in some food products as a preservative.

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.

Glyphosate is a chemical found in weed killer products such as RoundUpTM used on farms and home lawns. It gets absorbed by plant leaves, stopping plant growth within hours. Because of its effectiveness, glyphosate is found in widely used products that are easily obtainable. It is used all over the United States, but its highest concentrations are in the Midwest and Plains states.

It’s clear that not everyone responds to the same chemical exposures in the same way. There are many examples of this. The most striking is the person who smoked cigarettes for 30 years and never had breathing problems or developed lung cancer. A major factor in why this happens is “individual variability.”

Hydraulic fracturing (commonly known as fracking) is a technique that uses pressurized liquid to fracture bedrock in order to the extract the oil or gas inside. The process installs a steel pipe into a well bore and injects fracking fluid into the deep layers of rock. Once the rock is no longer able to absorb this fluid, it cracks. Materials in the fracking fluid keep these cracks open so the oil or gas beneath can flow freely and be collected. Fracking fluid usually consists of water, sand or beads, and a mixture of chemicals. After injection into the rock, some fracking fluid remains underground and some flows back to the surface. This flowback is meant to be collected for disposal.

Hydraulic fracturing, or hydrofracking, is a process for accessing gas and oil deep within the earth. The process involves creating a well and drilling about one mile deep into the ground. Once it has been dug deep enough, cement is poured into the opening around a steel pipe to create a barrier between the fracking process and underground water sources. Then the drilling continues deeper into the earth, this time at an angle until it becomes horizontal. The length of that horizontal drilling can last up to three miles in length. Next, more cement is poured around the hole to create a barrier with the surrounding environment. Then a perforating gun is sent down the well into the horizontal section. There, it punctures the bedrock, creating multiple cracks that are 30 inches deep.

Hydrogen sulfide is a colorless gas that has a strong rotten egg odor. It is produced naturally by the decaying process of organic matter and can also be released from crude petroleum, natural gas, and volcanic eruptions. Hydrogen sulfide is a very common gas that is generated in large farms and food processing plants, sewage treatment facilities, and landfills. Since it is such a common compound found in large industrial operations, the health effects of acute exposure to hydrogen sulfide are rather well defined. At high concentrations, at or above the National Institute for Occupational Safety & Health’s (NIOSH) Reference Exposure Level (REL) of 10 parts per million, exposure to hydrogen sulfide may cause irritation to the eyes and respiratory system. At higher concentrations, it can cause apnea, convulsions, dizziness, weakness, insomnia, and even death.

Radon is a colorless, tasteless and odorless gas that is radioactive and can cause cancer. It forms naturally when radioactive elements like uranium, thorium, or radium break down. This element can then move around in the environment by migrating as a gas or by dissolving in moving groundwater.

The main health concern surrounding radon is lung cancer. In the United States, radon is the second leading cause of lung cancer, after smoking. The Environmental Protection Agency (EPA) and the Surgeon General’s office estimate that radon is responsible for more than 20,000 lung cancer deaths each year in the country. This risk is greatly increased among people who smoke.

Isobutylene is a colorless gas that comes from natural gas. Its highly reactive nature makes it useful in the synthesis of many products including gasoline, rubber, plastics, resins, and other chemicals. Little toxicity information is known about isobutylene, and no occupational exposure limits are established, but exposure can cause irritation, headache, dizziness, and fatigue.

Lead is a naturally occurring element present in small amounts in the Earth’s crust. It has historically been used in many consumer products including gasoline, paint, plumbing materials, batteries, and cosmetics. This makes lead common all around us, in the air, water, soil, and buildings. Exposure to lead most commonly happens through ingestion or inhalation from lead paint, gas, pipes, or waste from industrial facilities that produce these products.

Manganese is a naturally occurring metal found in the environment. It is present in most foods (especially grains and beans), and our bodies need small amounts of it to function. Manganese is also used in manufacturing, most commonly to improve the strength of steel. Manufacturing use and improper disposal can release manganese into the air, water, and soil. Once in the environment manganese does not break down, so people can be exposed to high levels of manganese by breathing contaminated air, drinking contaminated water, or eating foods grown in contaminated soil.

Mercury is a naturally occurring metal that can be found in combination with other elements. It can be mined from the earth and also released as a byproduct from industrial facilities that manufacture chemicals. If mercury waste is not disposed of properly, it can enter the air, soil, and water. When mercury enters the water, it can build up in the tissues of fish in a process called bioaccumulation. Then, if people eat these contaminated fish, they can be exposed to high levels of mercury. Throughout the world, eating contaminated fish is the most common way people become exposed to mercury.

Methylene chloride (also known as dichloromethane) is a manmade chemical that is a clear liquid with a faintly sweet smell. It is used as an industrial solvent and an ingredient in paint strippers, so it is often used in commercial and do-it-yourself home improvement projects. Methylene chloride dissolves into the air, so the primary way people can be exposed to it is by breathing contaminated air. Because methylene chloride-containing products, like paint strippers, are often used in indoor spaces with little ventilation, people can easily be exposed to high levels of it. Inhaling methylene chloride causes brain dysfunction – confusion, inattentiveness, dizziness, numbness in the extremities, and even death. The World Health Organization, US Department of Health and Human Services, and US Environmental Protection Agency (EPA) all consider methylene chloride to likely cause cancer. The EPA estimates that 32,000 workers and 1.3 million consumers are exposed to methylene chloride every year.

Naphthalene is a solid chemical that easily evaporates. It is commonly found in coal, mothballs, and the manufacturing of polyvinyl chloride. Manufacturing, industrial releases, improper disposal of industrial waste, and consumer use can release naphthalene into the environment. Once released, naphthalene can evaporate into the surrounding air, dissolve in water, and stick to soil. Volatile organic compounds like naphthalene can adhere to particulates and travel with them through the environment. Breathing contaminated air, drinking contaminated water, or touching contaminated soil can expose people to naphthalene.

Particulate matter (PM) is a mixture of chemicals, dust, and liquid droplets that can be emitted into the air from automobiles, power plants, construction sites, smokestacks, and fires. When people breathe contaminated air, this PM gets lodged into people’s lungs and bloodstream. This worsens pre-existing lung diseases and can even cause lung disease, heart disease, and lung cancer. PM is categorized based on the size of particles it contains. PM with particles that are up to 10 micrometers in diameter are designated PM10. PM with particles that are smaller – up to 2.5 micrometers in diameter – are designated PM2.5.

Pentachlorophenol (PCP) is a manmade chemical that exists as solid crystals or flakes. Since the 1930s, it was used as a pesticide, disinfectant, and wood preservative. In the 1980s, its use became restricted to industrial purposes such as preserving wood on docks, railroads, and utility poles. PCP can enter the air, water, and soil from spills or improper waste disposal at facilities that use it. This can expose people who work at or live near facilities that use PCP. It can also evaporate from treated wood surfaces and enter the air, exposing people to chronic low levels of PCP in indoor and outdoor air.

Per- and polyfluoroalkyl substances (PFAS) are a class of chemicals that have been used since the 1950s in firefighting foams and many consumer products that includes firefighting foams, stain- and water-resistant fabrics, nonstick cookware and food packaging. PFAS chemicals are highly stable, so when they are released, people can be exposed through air, dust, food, and water resulting in widespread exposure.

Polybrominated Diphenyl Ethers (PBDE) are chemicals that are flame retardants – meaning they are added to different materials to make them less susceptible to fires. PBDEs are found in various everyday materials, such as furniture padding, computers, rugs, and electrical wires. They are a synthetic (not naturally found in the environment) subset of the organobromine compounds, chemicals where a carbon molecule is bonded to a bromine molecule. There are 209 different forms of PBDEs, which vary based on what the carbon-bromine structure looks like.

Polychlorinated biphenyls (PCBs) are a group of man-made chemicals that were used in industrial and commercial settings for their properties as electrical insulators. Their use was banned in 1979 but products containing them may still be in use. Despite this ban, there are several ways PCBs are still released into the environment today: through poorly maintained hazardous waste sites containing PCBs; leaks from electrical equipment; and accidental or deliberate dumping of PCB waste into sites not capable of handling them.

Polycyclic aromatic hydrocarbons (PAHs) are a class of chemicals that are formed in the incomplete burning of coal, oil, gas, or other organic matter. They can enter the air, water and adhere to particles in the soil. People are most likely to be exposed to PAHs by inhaling contaminated air. Workers at facilities that produce tar, asphalt, or incinerate trash are at the most risk; community exposure from vehicle exhaust, wood smoke, asphalt paving, or agricultural burning also occurs. Although less common, people can also be exposed by coming in contact with water contaminated with PAHs from discharges at wastewater treatment plants. The US Department of Health and Human Services classifies PAHs as “reasonably expected” to cause cancer. In animal studies, PAHs cause cancer, reproductive dysfunction, and birth defects.

Polyvinyl chloride, commonly known as “PVC” or “vinyl,” is the second largest commodity plastic in production in the world today, with an estimated 48.8 million tons produced worldwide in 2018. PVC is used in a wide range of products including pipes and tubing, school materials, product packaging, children’s toys, and several building materials.
Since it is such a common compound found in large industrial operations, the health effects of acute exposure to hydrogen sulfide are rather well defined. At high concentrations, at or above the National Institute for Occupational Safety & Health’s (NIOSH) Reference Exposure Level (REL) of 10 parts per million, exposure to hydrogen sulfide may cause irritation to the eyes and respiratory system. At higher concentrations, it can cause apnea, convulsions, dizziness, weakness, insomnia, and even death.

Radium is a naturally-occurring element found in soil, rocks, and water. Radium is radioactive, meaning its atoms are unstable and will decay over time. This process of radioactive decay produces gamma radiation, which can damage and mutate the cells in our body. This makes exposure to radium through inhalation or ingestion highly dangerous, leading to an increased risk of bone, blood, liver, and breast cancers. Even more concerning, radioactive decay of radium also produces the element radon, another radioactive element which causes lung cancer. The EPA classifies both radium and radon as known human carcinogens.

Radon is a colorless, tasteless and odorless gas that is radioactive and can cause cancer. It forms naturally when radioactive elements like uranium, thorium, or radium break down. This element can then move around in the environment by migrating as a gas or by dissolving in moving groundwater. The main health concern surrounding radon is lung cancer. In the United States, radon is the second leading cause of lung cancer, after smoking. The Environmental Protection Agency (EPA) and the Surgeon General’s office estimate that radon is responsible for more than 20,000 lung cancer deaths each year in the country. This risk is greatly increased among people who smoke.

It is difficult to interpret health risks when people are exposed to toxic chemicals. This is largely driven by the lack of information about what happens to people when they are exposed to toxic chemicals. In the face of this uncertainty, the government, primarily the USEPA, developed the process called “risk assessment” as the means for evaluating health risks.

Selenium is a mineral found in most rocks and soil across the globe. It can be extracted and processed from rock for commercial and manufacturing uses. About half of the processed selenium in the world is used in glass production. Another large portion of processed selenium is used in electronics, such as batteries, solar cells, and photoconductors, and the production of rubber, plastics, paints, and inks.

Sulfur dioxide is a gas with a strong odor that is released into the air through coal and oil burning. People can be exposed to sulfur dioxide by inhaling contaminated air. Workers at facilities where it is made as a by-product (such as power plants and fertilizer manufacturing plants) are most at risk, but anyone who lives near areas where sulfur dioxide is made may be in danger too.

Camp Lejeune is a US Marine Corps base established in 1942 in Jacksonville, North Carolina. In 1982 the Marine Corps found that drinking water from distribution plants serving the majority of the base was contaminated with volatile organic compounds.

It’s common to think that in science and technical information lies the answer to the many questions people ask about exposures to toxic chemicals. At CHEJ, we have not found this to be the case. While science and technical information is very important, by itself it cannot answer most of the questions people raise about exposure to toxic chemicals. People want answers and they want action to address the contamination in their community. Science and technical information can play a vital role in helping to achieve community goals, but identifying this role and learning how to use scientific and technical information is critical to the success of a local group.

Toluene is one of the most heavily produced chemicals in the US and the world. This chemical is utilized as an industrial solvent in the production of many commonly used materials such as paints, paint thinners, rubber, fingernail polish, lacquers, adhesives, and used extensively in the pharmaceutical industry.