California study finds no significant health risk from crumb rubber infill

Sacramento, California — A major California government study has found that recycled tire rubber used in synthetic turf fields poses no significant health risks to players or spectators.

The study, conducted by the California Office of Environmental Health Hazard Assessment (OEHHA), concluded that exposure to crumb rubber infill is “not likely to harm users or spectators”, including young athletes.

“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,” the agency said 9 March.

“This study should ease concerns about the safety of crumb rubber use in synthetic turf fields,” OEHHA director Kris Thayer said.

The research was carried out as part of California’s broader efforts to manage waste tires within a circular economy framework, where recycled materials are reused rather than landfilled.

The study examined 35 synthetic turf fields across California, covering both older and newly installed sites and representing different climate regions.

Researchers collected multiple samples from each field and conducted air monitoring both during “active use” and when no use occurred.

OEHHA said its study analysed more than 100 chemicals that could potentially pose health risks, unlike previous research which it said assessed only “a small number of chemicals.”

To identify possible exposure pathways, OEHHA worked with researchers from UC Berkeley and the University of Arizona, who analysed how players might come into contact with crumb rubber through skin contact, inhalation or accidental ingestion.

The researchers also surveyed more than 1,000 soccer players aged between seven and 71 to understand playing behaviour, including activities such as sliding or diving on the turf.

Because goalkeepers typically have the highest contact with the surface, the research used “goalie data” to estimate the risk for players.

The study also evaluated possible exposure among toddlers who might crawl on the turf.

“OEHHA found no acute risk to athletes, referees, coaches, or spectators, including toddlers,” said the agency.

In most cases, it said, risk of sensory irritation, cancer, harm to the reproductive system or a developing fetus, or other health effects were “negligible.”