In today’s world, parents and caregivers have enough to worry about when it comes to how environmental pollution and toxic chemicals affect our children. Our foods are often laden with pesticides, preservatives, and heavy metals (Arsenic in baby food! Mercury in fish!). There’s an alphabet soup of toxic chemicals in our everyday household products (PFAS in our nonstick pans! BPA in water bottles!). Keeping track of all the ways harmful chemicals in our environment might harm our kids can be exhausting.
Tell Congress: Protect Our Families From Harmful Toxic Chemicals
Forgive me, then, for adding yet another thing to your worry list: 6PPD, a chemical that has been added to tires and rubber products for decades, and one of its by-products, 6PPD-quinone (6PPDQ). While most of the focus on 6PPD has centered on how it impacts aquatic ecosystems, I recently learned there’s increasing concern about how it might be impacting human health. Read on for six things everyone should know about 6PPD and 6PPDQ:
1. 6PPD and 6PPDQ are extremely toxic.
6PPD is used to prevent cracks in rubber to improve durability. While tire manufacturers consider it important for safety, as it helps tires last longer for driving, when 6PPD reacts to the air, new chemicals are created—and one of those is 6PPDQ. It’s extremely toxic—best-known for its ability to kill coho salmon within hours of exposure. Because 6PPDQ was only discovered recently, there’s still a lot to learn about how it affects human health. But as a mom, I’m 100% certain that I don’t want my kids exposed to chemicals that kill fish.
2. 6PPD is everywhere, from playgrounds to waterways.
Rubber tires are a well-known source of 6PPD. The friction created when we drive generates tiny tire wear particles, which contain 6PPD that reacts with ozone in the air to become 6PPDQ.
Rainwater washes these tiny particles into storm drains and our waterways, like lakes, rivers, and streams. This process of stormwater runoff is how 6PPDQ reaches aquatic ecosystems and harms fish, like coho salmon.
Beyond tires, there’s also increasing concern about the prevalence of 6PPD in many other rubber-based products, including artificial turf, sneaker soles, doormats, garden hoses, and playgrounds that use crumb rubber.
3. 6PPD is dangerous for fish.
Scientists are still trying to understand which species are most vulnerable to 6PPDQ, what concentrations of exposure might be harmful, and whether there are long-term health effects in exposed species.
Coho salmon in the Pacific Northwest are the species most notably impacted by 6PPD in current research. In multiple studies, exposure to 6PPDQ caused their death within hours. This was a breakthrough discovery in 2020, after years of mysterious “urban runoff mortality syndrome” in salmon. For communities that depend on salmon ecologically, culturally, and economically, such as many Tribal communities, 6PPDQ’s harm to the species is a huge issue.
Other species of fish appear to be less sensitive to the effects of 6PPDQ, but research is ongoing and still in the early stages.
4. 6PPD is in our bodies.
There’s a lot we still don’t know about how 6PPD and 6PPDQ impact human health, but what we do know is worrisome. Because 6PPD has been used in tires and rubber products for decades, we do know 6PPD exposure can cause skin irritation, such as in workers at rubber plants, and research on animal models (mostly mice) has shown associations between 6PPD and liver damage and reproductive and developmental harm.
However, there’s more to know, especially about 6PPDQ. Recent biomonitoring research found both 6PPD and 6PPDQ in human urine samples, including in children. In one study highlighted by the Plastic Pollution Coalition, detection rates of both 6PPD and 6PPDQ were high across participants, and concentrations were especially high in pregnant women.
5. 6PPD is in the air we breathe.
Based on current science, likely pathways of exposure for humans include:
- Breathing air near traffic: Tire particles contribute to fine particle pollution. Given that communities of color and lower-income communities are more likely to live in areas impacted by traffic pollution, this is an issue of environmental justice.
- Contact with contaminated dust: Tire particles in the air can settle on streets, sidewalks, and eventually inside homes.
- Hand-to-mouth behaviors in children: Small children playing outside or on floors may ingest small amounts of contaminated dust.
6. We can all take steps to reduce our exposure to 6PPD.
We can’t individually solve tire chemistry concerns overnight, but we can take reasonable steps while pushing for systemic change. To minimize exposure to tire particles in dust at home:
- Leave shoes at the door, especially after children play on crumb rubber playgrounds or artificial turf.
- Wet-mop floors instead of dry-sweeping, which can kick dust into the air.
- Use a HEPA filter if you live near heavy traffic.
- Encourage kids to wash their hands after outdoor play.
To push for broader change, support strong toxic chemical protections and stay informed as research and policy on 6PPD and 6PPDQ evolves. There are currently no nationwide limits to 6PPDQ, which means that public awareness and advocacy matter. Our families and communities deserve transparency about the chemicals we’re exposed to—and we deserve strong federal and state policies that move as quickly as science does when harm becomes clear.
Tell Congress: Protect Our Families From Harmful Toxic Chemicals