Xylene or xylenes (used interchangeably) is a colorless, sweet-smelling chemical occurring naturally in petroleum, coal and wood tar. Xylene occurs in three forms – m-xylene, o-xylene, and p-xylene – and together they are referred to as xylenes. Like toluene, which was the subject of the previous Toxic Tuesday, xylene is an aromatic hydrocarbon that is used widely as a solvent in the printing, rubber, paint and leather industries. It is also commonly found as a solvent in pesticide products.

Xylene, being easily dissolvable in fats, also has similar health effects to toluene. Various central nervous system (CNS) problems are associated with exposure to xylenes in the air at levels as low as 100 parts per million (ppm) including headaches, dizziness, ataxia, drowsiness, excitement and tremors. At slightly more elevated levels (~200ppm), xylene can irritate the lungs, cause shortness of breath, and can cause pulmonary edema, a condition that results in excess buildup of fluid in the lungs. At larger concentrations, xylene may lead to liver and kidney damage and even cause cardiac abnormalities.

Given that xylene is a volatile organic compound (VOC), the main route of exposure is through inhalation. Automobile exhaust is one of the main sources of exposure. Hazardous waste disposal sites are another major route of exposure, given that xylene has been found in significant levels in over half of all Superfund sites. Finally, contaminated drinking water can be another significant route of exposure even if the water is not ingested.

This was the case in the village of Amesville, OH. CHEJ worked with some of the town residents to analyze the testing results of their drinking water supply after the inside of the town’s water storage tank was painted with an epoxy resin coat. Low but noticeable levels of xylene and other VOCs were found in their water supply. Despite being below the threshold of EPA’s federal drinking water standards, the constant exposure to xylene through ingestion, inhalation (e.g., showers), and dermal contact was a cause for concern. The cumulative and synergistic effects of multiple chemical exposures, such as the xylenes and the other VOCs in the case of Amesville, are very poorly understood and oftentimes result in higher incidences of disease even at very low levels of exposure.

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.

Toluene is a clear, colorless liquid that is found in vapor form at room temperature. A common sign of significant toluene concentration in the air is a sharp and sweet odor. At this concentration in ambient air, toluene can be a fire hazard given the fact that it can become flammable at temperatures above 40°F.

The main route of exposure to toluene is through inhalation. Once inhaled, toluene is easily absorbed by your lungs and dispersed through the body, even crossing the blood-brain barrier due to how easily it dissolves in fats (highly lipophilic). The result is a myriad of central nervous system (CNS) problems including headaches, dizziness, ataxia, drowsiness, euphoria, hallucinations, tremors, seizures, and even coma; as well as respiratory, cardiovascular, and reproductive/developmental effects.

Acute exposure to high levels of toluene (≥500 parts per million) can result in multiple CNS problems within 30-60 minutes of exposure. The respiratory system can develop irritated mucous membranes and liquid accumulation in the lungs, which can lead to respiratory arrest. Finally, even short exposures to elevated levels of toluene can result in irregular heart rhythm, making cardiac arrest much more likely after intense to moderate physical activity.

Prolonged exposure to toluene levels as low as 200ppm can cause chronic CNS problems such as headaches, fatigue, nausea and difficulty sleeping. Chronic irritation of the upper respiratory tract and sore throat have been reported in people exposed to small amounts of toluene for an extended period of time. Pulmonary lesions have been documented in long-term animal studies, so this can be a potential health complication for humans. Finally, although toluene has not been confirmed as a reproductive hazard, it is able to cross the placenta and is accumulated in breast milk, meaning that it can easily reach a developing fetus or newborn.

In developing countries, toluene has become a cause for major concern due to a practice among children and young adults called glue sniffing. Glue sniffing is a form of substance abuse common in many developing countries due to its relatively inexpensive nature. The high and euphoric feelings that it produces are partly due to the ability of toluene to easily enter the central nervous system and create hallucinations and euphoria. A number of studies around the world, including in places such as Singapore; South Africa; and India, have documented this practice and have offered insights into how to combat this practice.

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.

In November 2019, multiple fires and explosions occurred at a facility manufacturing 1,3-butadiene in Port Neches, Texas. There was a mandatory two-day evacuation of residents within 4 miles of the site, but soon after they were allowed to return, residents received another evacuation order because conditions had not improved. The facility, owned by Texas Petroleum Chemicals Group (TPC Group) had a long history of violating state and federal air emissions regulations. It released more air pollution than allowed by its permits on 6 occasions in 2019 and over 70 times in the last decade. TPC Group was fined for these violations, but these fines were clearly not a deterrent to the corporation breaking the rules and endangering the health of surrounding residents. In fact, in a settlement with the Environmental Protection Agency after releasing huge amounts of 1,3-butadiene in the air in 2017, TPC Group was required to monitor 1,3-butadiene levels. That’s how a 2020 report found that in the months leading up to the explosions, the facility started releasing massive amounts of 1,3-butadiene into the air. Because chemicals in the air can travel large distances, we don’t know how many people may have been exposed to his cancer-causing agent because of TPC Group’s disregard for regulations. The current system of monitoring emissions and imposing nominal fines on facilities that exceed them is not working to keep people safe. Tougher regulations, harsher penalties, and revocation of permits must be considered as we fight to protect communities from corporations using harmful chemicals.