In Lookout Eugene-Springfield’s environmental and public health coverage, complex science often intersects with real-world impacts.

And complex science often goes hand-in-hand with complicated terms. This glossary is meant to help you understand those terms as you read our reporting — from the Superfund site at J.H. Baxter to landfill management in Lane County.

Chemicals of concern

Pentachlorophenol 

Pentachlorophenol, or PCP, is a highly toxic, human-made chemical that does not break down easily in the environment.

PCP is a solid chemical that looks like a white or colorless powder or needlelike crystals. PCP is a waxy substance created in a chemical factory. It was widely used as an industrial wood preservative, mainly to treat utility poles until the federal Environmental Protection Agency ordered a phase-out in 2022.

It was commonly mixed with diesel fuel or kerosene so it could soak into wood under high pressure and temperatures. Typical mixtures were about 5% PCP and 95% diesel or kerosene.

Dioxins (defined below) are not part of PCP itself, but they can be created during the manufacture of PCP or later if treated wood is burned or overheated.

What PCP means for health: Exposure to pentachlorophenol through air or water may increase cancer risk, including non-Hodgkin lymphoma, according to the National Toxicology Program. Studies have also linked PCP exposure to damage to organs such as the liver and kidneys, as well as reproductive harm. Short-term or high-level exposure can cause headaches, trouble breathing and high fevers.

Dioxins 

Dioxins are a group of highly toxic chemical compounds that can appear as a white powder or small crystals. They were present as contaminants in Agent Orange, the herbicide used by the U.S. military during the Vietnam War. Dioxins can attach to soil and dust particles and persist in the environment.

PCP and dioxins are both chlorine-based organic chemicals. When PCP is made, the process uses heat and chlorine. Under those conditions, some of the chemicals can accidentally rearrange and bond in a different way, forming dioxins instead of PCP.

The same thing can happen later if PCP-treated wood is burned or overheated. High, uncontrolled heat can break PCP molecules apart and allow them to recombine into dioxins.

What dioxins mean for health: Dioxins are highly toxic and can cause cancer, reproductive and developmental problems, damage to the immune system, and can interfere with hormones, according to the EPA. 

Landfill activity 

Leachate 

Leachate forms when liquid, such as rainwater, moves through solid materials like trash and picks up chemicals and contaminants along the way. Landfill managers and hazardous-waste researchers sometimes refer to leachate informally as “garbage juice.”

If not contained, leachate can move through soil in ways similar to groundwater and travel beyond the boundaries of a landfill. That movement is especially concerning at sites where hazardous chemicals or industrial waste were disposed of.

Under current laws, modern landfills are required by current law to have impermeable liners designed to keep leachate from seeping into surrounding soil and groundwater. 

What leachate means for health: Leachate moving through groundwater has potential to reach drinking water supplies, rivers or other water sources, potentially exposing people to harmful chemicals, according to the EPA.

Laws and policies

Superfund 

The Environmental Protection Agency manages Superfund sites in its National Priorities List, which was created under the Comprehensive Environmental Response, Compensation, and Liability Act — often referred to as the Superfund law. A Superfund site is contaminated property, often polluted with chemicals that are dangerous to humans. This priorities list is the basis for federal funding to support longterm cleanup, in many cases when the responsible parties can’t pay. Learn more about what a Superfund site means here. 

Resource Conservation and Recovery Act 

While similar to Superfund, the Resource Conservation and Recovery Act is a separate law with a different purpose. Superfund focuses on cleaning up and redeveloping contaminated sites, while the Resource Conservation and Recovery Act governs how hazardous waste is handled and monitored.

Looking for other details? 

This is an ongoing list of terms. If there is a word or concept you’re curious about and don’t see here, email newsroom@lookoutlocal.com

Ashli Blow brings 12 years of experience in journalism and science writing, focusing on the intersection of issues that impact everyone connected to the land — whether private or public, developed or forested.