This is the 2026 Science on Rubber Mulch Toxicity
If you’ve been researching rubber mulch for your playground, garden, or landscaping project, you’ve probably encountered some concerns about its safety. It’s a fair question. After all, rubber mulch is made from recycled tires, and tires contain a complex mixture of chemicals. So is rubber mulch actually toxic? The short answer is no, and the science to back that up has never been stronger.
Where the Concern Comes From
Recycled tire rubber contains compounds including polycyclic aromatic hydrocarbons (PAHs), zinc, and other chemicals that, at high concentrations, can pose health risks. Early concerns were largely driven by the widespread use of crumb rubber on synthetic turf athletic fields, where children and athletes spend significant time in direct contact with the material — rolling, falling, and sometimes ingesting small particles.
Those concerns prompted some of the most rigorous independent research ever conducted on the subject. And the results have been consistently reassuring.
What the Science Actually Says
The U.S. EPA and CDC Weigh In
In April 2024, the U.S. Environmental Protection Agency and the CDC’s Agency for Toxic Substances and Disease Registry (ATSDR) published the final results of their joint Federal Research Action Plan (FRAP), a multi-year, peer-reviewed biomonitoring study specifically designed to measure real-world human exposure to chemicals from recycled tire crumb rubber.
The study followed 161 participants ages 7–77, collecting urine samples before and after play on both tire crumb rubber turf fields and natural grass fields. The findings were clear:
- There was no meaningful difference in chemical exposure between players on crumb rubber fields and those on natural grass
- The best predictor of post-activity chemical levels was each participant’s pre-activity baseline — meaning the fields themselves were not elevating exposure
- Participants’ PAH levels were actually lower than the general U.S. population as measured by the national NHANES health survey
“The results of this study did not indicate that use of [tire crumb rubber] fields leads to increased exposure to PAHs compared with natural grass fields.” From: EPA/CDC Federal Research Action Plan Final Report, April 2024
California’s Landmark Study — March 2026
In March 2026, California’s Office of Environmental Health Hazard Assessment (OEHHA) — the state’s own lead agency for environmental health risk assessment, and one of the most rigorous such bodies in the country — published the results of a landmark study on recycled tire crumb rubber.
The study was exceptionally thorough:
- Tested 35 synthetic turf fields across all of California’s climate regions
- Examined more than 100 chemicals — far more comprehensive than earlier studies
- Simulated sweat and digestion to model real-world chemical uptake
- Surveyed more than 1,000 athletes ages 7–71 on their actual behavior and contact patterns Used goalie behavior — the most intensive, highest-contact scenario — as the worst-case exposure model
- Studied exposure risks even for toddlers crawling on fields
The conclusion, in the words of OEHHA Director Kris Thayer:
“There is no evidence of significant risk for cancer or other health problems from this recycled rubber to players, coaches, referees and spectators based on the available data, even for young athletes.”
How the Two Studies Compare
Together, these two studies represent the most comprehensive body of evidence ever assembled on the safety of recycled tire rubber. They approached the question differently — and both arrived at the same answer.
The fact that two independent bodies — one at the state level, one at the federal level — reached identical conclusions using entirely different methodologies makes this one of the most well-supported safety assessments in consumer product research.
What This Means for Rubber Mulch Specifically
It’s worth noting that both of these landmark studies focused on synthetic turf fields, where crumb rubber is used as a loose infill that athletes have extensive direct contact with — arguably a higher-exposure scenario than rubber mulch used in a garden bed or under a backyard playset. If recycled tire rubber poses no significant risk in that intensive-contact setting, the case for safety in typical rubber mulch applications is even stronger.
Rubber mulch used in landscaping and playground surfacing sits on top of the ground, is not typically ingested, and is not regularly disturbed the way turf infill is. The exposure pathway is considerably more limited.
Frequently Asked Questions
Is rubber mulch safe for children to play on?
Yes. Both the EPA/CDC and California’s OEHHA have independently concluded that recycled tire rubber poses no significant health risk even to young children, including toddlers with direct, intensive contact. Rubber mulch in a playground setting represents a lower exposure scenario than the athletic turf fields studied.
Can rubber mulch cause cancer?
Based on the available science, no. The OEHHA’s March 2026 landmark study specifically found “no evidence of significant risk for cancer” from recycled rubber, even when modeling worst-case exposure scenarios for young athletes. The EPA/CDC study likewise found no elevated chemical exposure compared to natural grass.
Is rubber mulch safe for pets?
Rubber mulch poses no known toxic risk to pets under normal conditions. The chemical concerns associated with recycled tire rubber, primarily PAHs, were studied extensively in humans and found to be non-significant. If your pet occasionally mouths or chews rubber mulch pieces, consult your veterinarian, but incidental contact is not a documented health concern.
What chemicals are in rubber mulch?
Recycled tire rubber can contain trace amounts of polycyclic aromatic hydrocarbons (PAHs), zinc, and other compounds. The OEHHA study examined more than 100 such chemicals and found that none reached levels posing a significant health risk under realistic exposure conditions.
Is rubber mulch safer than wood mulch?
From a toxicity standpoint, both are considered safe for typical residential use. Rubber mulch has the added advantage of not harboring termites, mold, or fungi, all of which can be concerns with wood-based mulches. It also doesn’t splinter, making it a safer surface choice for children’s playgrounds.
Why were these studies done on turf fields rather than rubber mulch directly?
Synthetic turf fields use crumb rubber from the same recycled tire source as rubber mulch, and they represent the highest possible exposure scenario, athletes rolling on the surface, ingesting particles, and spending hours in direct contact. By studying the worst-case scenario and finding no significant risk, scientists have effectively set a safety ceiling that typical rubber mulch use falls well below.
Peace of Mind Comes Standard
The science is clear. Rubber mulch is safe, tested, and trusted by families, schools, and communities across the country. Whether you’re surfacing a backyard playset, a school playground, or a garden bed, our landscape rubber mulch delivers lasting protection you can feel good about.
Full blog post: https://rubbermulch.com/blogs/rubbermulch/is-rubber-mulch-considered-toxic-the-answer-in-2026-is-no
Sources:
- U.S. EPA & CDC/ATSDR, Synthetic Turf Field Recycled Tire Crumb Rubber Research Under the Federal Research Action Plan — Final Report, April 2024
- California Office of Environmental Health Hazard Assessment (OEHHA), Landmark Study Finds No Significant Risk from Key Component of Synthetic Turf Fields, March 2026
