Artificial turf and crumb rubber infill (synthetic sports fields and backyard grass) — outdoor safety profile

What is this product?

Artificial turf with crumb rubber infill — used on soccer fields, football fields, baseball diamonds, playgrounds, and increasingly residential backyards — combines synthetic polyethylene or polypropylene grass fibers with a base layer of granulated recycled automobile tire rubber (crumb rubber) as infill material. Approximately 40,000 automobile tires' worth of crumb rubber are used in a single full-size soccer field installation. Automobile tires contain a complex chemical mixture developed over decades of tire manufacturing: polycyclic aromatic hydrocarbons (PAHs) from process oils and rubber manufacturing — including IARC Group 1 carcinogen benzo[a]pyrene; volatile organic compounds including benzene, toluene, ethylbenzene, and xylene (BTEX); heavy metals including zinc (15,000–25,000 ppm from vulcanization), lead, and cadmium at lower concentrations; carbon black (IARC Group 2B); and various rubber additives including benzothiazole and diphenylguanidine. Children playing on synthetic turf are exposed through multiple pathways: dermal contact with heated crumb rubber particles; oral ingestion of crumb rubber particles that enter the mouth during play; and inhalation of volatile compounds off-gassed by the heated rubber surface. The temperature amplification effect is a significant exposure modifier: black crumb rubber in direct summer sunlight on synthetic turf fields reaches surface temperatures of 50–70°C when ambient temperatures are 30°C — the solar-heated rubber generates a substantially elevated VOC plume above the turf surface compared to the same rubber at ambient temperature. Goalkeepers and players making sliding tackles have the highest cumulative crumb rubber exposure because they spend significant time lying on the turf surface in direct contact with the infill. In 2016, the CDC and EPA initiated a joint study of potential health risks from crumb rubber infill following concerns raised by University of Washington soccer coach Amy Griffin, who had been tracking cancer diagnoses among youth soccer players — particularly goalkeepers who played on synthetic turf. The study documented concerning chemical compounds in crumb rubber but was not completed due to resource constraints, leaving the health risk characterization incomplete. A distinct emerging concern is PFAS in synthetic turf fibers: some manufacturers apply PFAS coatings to synthetic grass fibers for UV and abrasion resistance; these fibers would contribute to PFAS exposure via dermal contact and oral ingestion of fiber fragments during play.

What's in it

Click any compound name for its full safety profile, regulatory consensus, and exposure data.

Who's most at risk

• Children — Developing endocrine and neurological systems, higher exposure per body weight

How to use it more safely

• Use in well-ventilated outdoor areas away from children's direct contact
• Install on properly drained, compacted base to prevent water pooling and bacterial growth
• Regular maintenance including removal of debris and periodic cleaning to reduce contamination
• Ensure crumb infill meets ASTM F3440 standards for heavy metal content limits

Red flags — when to walk away

• Child goalkeeper or ground-contact sport athlete spending significant time on synthetic turf fields with crumb rubber infill — especially during hot weather; residential synthetic turf installation with crumb rubber infill where children play daily — Youth soccer goalkeepers on synthetic turf fields represent the highest-exposure scenario for crumb rubber chemical exposure: extended time in direct physical contact with the turf surface, hands and arms in the crumb rubber, elevated temperatures increasing VOC off-gassing, during the developmental period when carcinogen exposure has longest to manifest. Amy Griffin's observations — enough of an epidemiological signal to initiate a CDC/EPA joint study — came from tracking cancer diagnoses in this specific population. The CDC/EPA study confirmed the presence of concerning chemicals; it did not definitively rule out elevated risk. Under uncertainty about a potential carcinogen exposure, minimizing exposure of developing children is the rational precautionary response.
• Synthetic turf surface temperature during hot sunny days — children lying or rolling on field surface in summer; field in direct sunlight during midday hours when surface temperatures reach 50–70°C — The surface temperature of black crumb rubber in direct sunlight is the primary modulator of VOC off-gassing intensity. A field surface at 60°C releases BTEX and PAH vapors at a rate orders of magnitude higher than the same surface at 20°C. Children lying on hot turf receive both dermal contact exposure to heated crumb rubber and inhalation exposure to the elevated VOC plume directly above the surface. High-intensity summer practice sessions on hot synthetic turf are the scenario with the highest acute chemical exposure intensity.

Green flags — what to look for

• Natural grass field; synthetic turf with documented alternative infill (cork, coco, TPE virgin rubber, or silica sand — not crumb rubber); PFAS-free synthetic turf fiber documentation; post-game handwashing protocol in place for athletes — Alternative infill materials from controlled virgin sources have substantially lower PAH, BTEX, and heavy metal chemical profiles than recycled tire crumb rubber. PFAS-free fiber documentation addresses the emerging PFAS concern distinct from crumb rubber chemistry. Handwashing after play on synthetic turf removes crumb rubber particles from hands before they can be transferred to the mouth during food consumption — a simple, free, effective exposure reduction step.

Safer alternatives

• Natural grass or sod — Eliminates chemical exposure and heavy metal concerns; biodegradable and safer for children
• Organic cork or coconut husk infill — Natural, non-toxic alternative infill reducing chemical leaching and heavy metal risks
• Thermoplastic polyurethane (TPU) infill — Engineered alternative to crumb rubber with lower off-gassing and heavy metal concerns

Frequently asked questions