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.

Acrylonitrile is a clear liquid that smells like onions or garlic. It is man-made as it does not naturally occur on Earth. It is used to create other materials, most commonly acrylic fibers in clothing and carpeting. Acrylonitrile can enter the environment from industrial sites that produce it and waste sites where it is disposed of. Because it dissolves easily in water and readily evaporates, it can enter the water, air, and soil. Although acrylonitrile breaks down in water and soil, people can still be exposed to it if they live or work near factories that use it. They can also be exposed to it through acrylonitrile-based plastic products and acrylic fibers. In addition to industrial sources of exposure, acrylonitrile is also found in tobacco smoke and vehicle exhaust.

Inhaling airborne acrylonitrile can cause respiratory, skin, and eye irritation. It can also cause dizziness, headaches, weakness, impaired judgment, and, in extreme cases, convulsions. Exposure of acrylonitrile to the skin can cause burns and blisters, and repeated exposure can cause brain and liver damage. Studies on laboratory animals have also found that inhalation or oral exposure can cause low birth weights and birth defects.

The US Department of Health and Human Services, the US Environmental Protection Agency, and the International Agency for Research on Cancer have all determined that acrylonitrile probably causes cancer in humans. This is likely to occur through DNA damage. Research has found that people who work at facilities that use acrylonitrile have higher rates of lung cancer than the general population. Acrylonitrile is also one of the chemicals in tobacco smoke that is most associated with respiratory cancers. These findings demonstrate that acrylonitrile is dangerous enough that people need to be protected from it, especially if they live or work near facilities that use or dispose of it.