Science has spoken on recycled rubber. Now, cynics are moving the goalposts … again.

Parks directors, parents, and advocates have long asked for definitive research on the use of recycled rubber in parks and playing fields. That is exactly what the California Office of Environmental Health Hazard Assessment (OEHHA) and the California EPA has provided with the just-finalized study on crumb rubber, the most comprehensive to date. 

California, which takes a backseat to no one on environmental and health issues, has given us crystal clear findings that these fields are safe to use. California’s leading researchers found that the use of crumb rubber poses “no significant risk” for players, coaches, and others using turf fields. 

Are critics and cynics satisfied? No, of course not. Faced with this body of definitive science, they have moved the goalposts again and made clear that there is no scenario in which they’d use the material. In their world, people would only play on beautifully manicured “pitches” (with no pesticides or fertilizer of course).

But here in the real world, we want people to use parks, playgrounds, and playing fields as much as possible. With changing weather patterns, grass fields are hard to maintain and often become muddy and torn up during inclement weather, leading to frequent closures.

Young people, and people of all ages, need places to be active and gather outside, away from the allure of screens. Turf fields with recycled rubber infill provide a great playing surface and can be utilized at much higher rates than grass. OEHHA’s research provides the most in-depth evidence to date that these fields are safe for communities.

But the findings, which add to years of additional research, are simply not enough for some skeptics, who would have us set a bar that no material could possibly clear.

The fact is that the study is clear cut. California researchers looked at this issue from nearly every angle, over the span of a decade, and solicited public comment throughout the process. 

The research included:

• 35 turf fields across the state, studying field users across every age range, from toddlers crawling to grandparents cheering from the sidelines
• 148 chemicals that might present risk, evaluated across three exposure pathways: ingestion, inhalation, and skin contact
• Biomonitoring and the use of artificial sweat and gastric juices to determine how often bodily fluids take up chemicals that pose health risks

From there, OEHHA scientists evaluated a variety of potential health impacts. They analyzed whether those using the fields were susceptible to everything from cancer and reproductive system damage to sensory irritants affecting the eyes and airways.

"The study did not find any chemical exposures associated with the turf fields that would pose immediate (acute) health hazards,” OEHHA wrote. They found that exposure to substances that pose risk to reproductive health is of “low concern,” and that cancer risks are “insignificant” for athletes, coaches, and referees.

Other reports, including the 2024 joint study from the U.S. EPA, CDC, and CPSC, have looked at crumb rubber and come to similar conclusions. None, however, have looked at the issue as comprehensively as CalOEHHA. 

Safe and healthy playing surfaces keep people of all ages active and together. We should be opening up opportunities for consistent field access, not closing them down. 

Here’s OEHHA Director Kris Thayer:

"This study should ease concerns about the safety of crumb rubber use in synthetic turf fields," said Thayer. "Athletes of all ages can use these fields without parents worrying about this commonly used material."

OEHHA makes it clear that local leaders can confidently choose synthetic turf fields to improve field quality, reduce closures, and ensure safe, year-round play across sports and activities.