Potentially hazardous synthetic turf that's being targeted in a health bill by state Sen. Jerry Hill is used on some City of Palo Alto and school district playing fields, officials have confirmed.
On Dec. 17, Hill introduced Senate Bill 47, which would require the state Office of Environmental Health Assessment to conduct a comprehensive study of the effects of several chemicals released from turf made out of ground, recycled tires, also known as crumb rubber. The bill would significantly expand a 2010 Environmental Health Assessment study that identified 30 different volatile organic compounds in air samples emanating from crumb-rubber turf and playground surfaces that use the material.
Gunn High School has the turf on its football field and baseball infield, as does Palo Alto High School on its football field, baseball infield and El Camino soccer field, said Bob Golton, manager of Palo Alto Unified School District Strong Schools Bond.
The turf has three layers: a bottom layer of silica sand, a middle layer that is a mixture of sand and crumb rubber, and a top layer composed of polyethylene-blend fibers and crumb rubber. The fibers are meant to replicate blades of grass, while the infill acts as a cushion, he said.
The City of Palo Alto also has crumb-rubber playing fields at the Stanford Palo Alto Playing Fields (El Camino Real and Page Mill Road) and at Cubberley Community Center, according to Daren Anderson, manager of the city's Open Space, Parks and Golf division.
Many of Palo Alto's playgrounds also have rubber play surfacing. The latter is comprised of a cushion made of recycled tire rubber and a decorative wear layer of Ethylene Propylene Diene monomer) or TPV (Thermal plastic vulcanized) granules. It is one of the best surfaces for ADA accessibility, he added.
The city plans to replace the Stanford Palo Alto Playing Fields this June and Cubberley's in 2019 with an alternative synthetic-turf product, he said. El Camino Park, which is undergoing a renovation this year, will have synthetic turf installed, but it will not be crumb rubber.
The average lifespan for a synthetic field is about eight to 10 years, and the fields will be replaced within that time span, he said.
Golton said the Gunn and Paly fields were installed between 2008 and 2010. The district does not have any plans to replace them.
Of the compounds identified in air samples in the state's 2010 study, 14 volatile organic compounds, or VOCs, came solely from the crumb-rubber fields. The others were also found above natural turf (which were used as "control" air samples).
The 14 chemicals measured were not found consistently on all of the artificial fields, the study noted. Researchers ultimately focused on seven chemicals for potential hazardous effects from acute or chronic exposure: 2-Propanol; Cyclohexane; Toluene; m, p, o-xylenes; Isopropylbenzene; 4-Ethyltoluene; and 1, 2, 4-Trimethylbenzene.
State officials have so far concluded that the amount of off-gassing and inhaled particle size did not arise to the level of a human hazard.
But the research had a number of gaps and inconsistencies, they noted.
The study was limited to just four artificial fields. And it did not look at heavy metals, which might be inhaled, touch people's skin or get into abrasions during play. Researchers also found little consistency in the types of chemicals from field to field, perhaps because of differences in the rubber between products, they said.
Hill's bill would seek to answer those and other health-related questions. SB 47 would require a study of at least 20 synthetic-turf fields and playgrounds throughout the state. And the bill calls for the examination of many heavy metals, such as arsenic, barium, chromium, lead and mercury.
Researchers would also analyze exposure to chemicals including aromatic hydrocarbons, acetone, benzene and naphthalene. They would examine effects based on the cumulative length of play, whether children potentially ingest the materials and the potential for the artificial surfaces to cause non-Hodgkin lymphoma, testicular and prostate cancer, sarcoma and leukemia.
Hill's law would also compare the potential hazards in crumb-rubber turf surfaces with those made of alternative materials such as coconut fibers, rice husks, cork and used shoes.
Results of the studies would be posted on the Environmental Health Assessment office's website by July 1, 2017. Public and private schools and local governments would be banned from installing new synthetic-turf fields and playground surfaces until Jan. 1, 2018.
Costs for the studies would come from the California Tire Recycling Management Fund, which subsidizes programs related to waste-tire disposal.
If passed, the law would also require a comparison of infection rates between athletes who played on artificial and those on natural turf, which the 2010 research did not conduct. The 2010 study did examine bacteria at five artificial- and two natural-turf fields in the Bay Area. The artificial turf yielded from four to 10 different species of bacteria per field, compared to 11 to 14 per natural turf, according to the study.
The researchers concluded that artificial turf decreased the risk of infection compared to natural turf. But the rate of artificial-turf skin abrasions was two to three times higher. And abrasiveness could influence the frequency of bacterial infections, the researchers noted.
Palo Alto city and school district officials said their fields are inspected and cleaned regularly.