When parents at Crocker/Riverside Elementary have asked the district to justify the safety of the proposed artificial turf installation, the district has consistently pointed to one source: the California Office of Environmental Health Hazard Assessment (OEHHA) study on synthetic turf, finalized in March 2026. Assistant Superintendent Chris Ralston has cited it in writing across multiple emails. The district has cited it publicly. CBS Sacramento reported the district’s position as California research that found no significant risk from synthetic turf fields.
There is a serious problem with this argument. The OEHHA study does not cover the product the district is installing, and it does not cover the children who will be playing on it.
The most remarkable part is that Ralston himself has admitted both of these things in writing. And — as documented below — OEHHA itself has formally acknowledged the same limitations the district has spent months minimizing.
This article documents what the OEHHA study actually was, what it actually concluded, what it did not study, what its own scientific advisory panel raised about its design, and how the district’s own facilities administrator has conceded — on the record — that the study cannot support the decision he is using it to defend.
What the OEHHA study actually was
The OEHHA study was a multi-year investigation into the health effects of synthetic turf fields filled with crumb rubberinfill — that is, ground-up recycled tires. It was the most comprehensive state-level review of crumb rubber turf ever conducted in California. It examined chemical exposures, cancer risk, dermal contact, inhalation exposure, and ingestion pathways.
The study’s design was specific. Its sample population was specific. Its product scope was specific. And every one of those specifics matters.
The OEHHA study evaluated crumb rubber. Period. Full stop.
It did not evaluate olive pit infill. It did not evaluate cork infill. It did not evaluate any of the alternative infill products that have come onto the market in the years since.
This is not a matter of interpretation. It is a matter of what the study itself examined. As OEHHA’s own staff toxicologist Dr. Jocelyn Claude told the Scientific Advisory Panel on April 28, 2025: “Our study focused on specifically the crumb rubber in-fill… We did not specifically look at blades or the backing materials on these fields.” CA
What product the district is installing
The product specified for Crocker/Riverside Elementary is the FieldTurf Vertex Prime PureSelect system with 2.1 pounds of PureSelect Olive infill per square foot, confirmed in FieldTurf’s pricing proposal dated March 25, 2026.
This is not crumb rubber turf. The infill is mechanically pulverized olive pits, an agricultural byproduct that FieldTurf has marketed as a “natural” alternative to recycled rubber.
Olive pit infill is a different product, with different material properties, different particle behavior, different chemical composition, and different exposure characteristics from crumb rubber. The OEHHA study examined none of it.
The district has been forthright on at least this point. Ralston himself described olive pit infill in writing as “a new product.” When pressed in his March 12, 2026 email defending the project, his exact framing was: “Several of the concerns raised have been studied at the state level and are discussed in the OEHHA report on synthetic turf from 2019.”
He then attached the OEHHA study and pivoted: “The product we are using uses olive pit infill instead of crumb rubber, consistent with what we did last summer at JFK High School.”
In a single paragraph, he cited the study to suggest the concerns had been addressed, and then immediately acknowledged the product the study examined is not the product being installed.
OEHHA itself acknowledges the study has serious limitations
This is not a fringe argument made by concerned parents. It is OEHHA’s own formal position.
In its final report, released March 5, 2026, OEHHA explicitly identified several noteworthy study limitations, including: the study evaluated exposures to crumb rubber infill only, and not backing materials such as grass blade components; the study did not assess degradation products including microplastics and particles; and the study did not address field runoff or ecological impact CA.
Each of these limitations is fatal to the district’s use of the study as safety clearance for the Crocker/Riverside installation:
Limitation 1 — Infill only, not backing or blades. OEHHA’s own conclusion is that the study did not examine the synthetic carpet itself. Yet independent testing has consistently found PFAS — “forever chemicals” linked to cancer, immune disruption, and developmental harm — in the plastic blades and backing of artificial turf. There is documented evidence of PFAS in turf backing. National Collaborating Centre for Environmental Health Changing the infill from crumb rubber to olive pit does not change what is in the synthetic carpet. OEHHA has formally stated it did not study that part.
Limitation 2 — No microplastic or degradation analysis. As artificial turf ages and is subject to UV exposure, foot traffic, and Sacramento heat, the synthetic fibers degrade. Children inhale, touch, and sometimes ingest the resulting particles. OEHHA has acknowledged it did not assess this exposure pathway at all.
Limitation 3 — No field runoff or ecological impact. OEHHA has acknowledged the study did not examine what happens when chemicals leach from the field into surrounding soil and stormwater. The Crocker/Riverside field abuts private backyards, residential gardens, and a Disadvantaged Community census tract.
These are not parent talking points. They are limitations OEHHA itself has formally identified in its own published report.
What the OEHHA Scientific Advisory Panel raised about study design
OEHHA’s study was reviewed by a Scientific Advisory Panel of seven outside experts in exposure science and biomedical research. The panel met five times across nearly a decade. The transcripts of those meetings are publicly available — and they document, in the panel’s own words, methodological concerns the district has not disclosed to parents.
At the final SAP meeting on April 28, 2025, panel member Dr. Deborah Bennett of UC Davis raised concerns about how OEHHA had handled exposure duration for child athletes. After OEHHA explained that it had used the mean exposure duration rather than capturing the longest tournament-day exposures, Bennett pushed back directly. From the meeting transcript:
“Because if the DART [developmental and reproductive toxicity] is a health end point applicable to a one-day exposure, there’s a lot of kids that play in tournaments… they would be at Stockton at 8:00 a.m. and they would be there on the field until 5:00 p.m. and back the next day for a repeat encore.” CA
Bennett’s concern, in plain English: OEHHA’s exposure modeling used average exposure times — roughly the duration of one game — when in reality many children spend full days on artificial turf at tournaments. Using the mean rather than realistic high-end exposures may underestimate the actual dose children receive on heavy-use days.
OEHHA’s own staff acknowledged the issue and committed to revisit it: “So we can revisit it to kind of see what — when we take out what that kind of high-end mean looks like to see if maybe we can use something to better represent if there was a tournament several days.” CA
This is the panel doing its job. It is also a documented limitation in how OEHHA modeled the very exposure pattern most relevant to elementary school children, who use these fields not for one game but for full days of recess, P.E., and after-school programming throughout the week.
What the panel could not study because the data did not exist
A second methodological concern the panel raised goes to the heart of the district’s reliance on this study for elementary children specifically. The OEHHA study’s exposure parameters for the youngest children — infants and toddlers ages 0 to 2 — were derived not from direct study of children’s behavior on synthetic turf playing fields, but from archived video footage of children playing on synthetic turf or in playground settings CA, used to develop “mouthing frequency parameters specifically for the infant spectators on the field.”
For the elementary-age children at Crocker/Riverside — ages 5 through 11 — there is no comparable behavioral dataset in the OEHHA study at all. The study evaluated athletes, soccer coaches, referees, as well as spectators CA, with check marks for which age groups received which assessment. Elementary-age children at recess, lunch, and P.E. on a synthetic turf field do not fit any of the study’s behavioral profiles.
OEHHA’s study chair, Dr. John Balmes of UC Berkeley, acknowledged that the study was a complex, decade-long effort released after significant delays. Its scope was, by necessity, finite. That is not a criticism of the study — it is a statement about what the study can and cannot tell a school district that is making decisions about elementary-age children on a different product than the one OEHHA examined.
Even on its own terms, the OEHHA study did not give a clean bill of health
A frequently overlooked finding in the OEHHA study itself: the study found a slightly higher increase in average cancer risks for spectators 0–2 years of age — an average of 1.1 additional cancer cases in one million during a lifetime. These risks were considered low, but still a possible concern due to potential for hand-to-mouth ingestion of crumb rubber infill by infants. City of Millbrae
Even within the study’s own findings, the population most similar to elementary-age children — small children with high hand-to-mouth contact rates — was the population for which OEHHA flagged elevated risk. And that finding was for crumb rubber, the product the district is not installing. The product the district is installing — olive pit infill — has not been evaluated for the same risk pathway by any government health agency.
Ralston’s first written admission: the study has limitations for this population
On March 25, 2026, in response to a parent’s detailed analysis of the OEHHA study’s limitations, Ralston wrote a sentence that should appear in every conversation about this project:
“I cannot disagree with your summary of the study, except that it is a tool to help make better decisions.”
That admission cannot be walked back. It is in the written record. The district’s chief facilities decision-maker — the person responsible for selecting this product — has conceded in writing that he agrees with a parent’s assessment that the OEHHA study has limitations.
He did not dispute the substance of the parent’s critique. He simply added that the study, despite its acknowledged limitations, is “a tool to help make better decisions.”
A study with admitted limitations is not a clearance. It is exactly what Ralston himself called it: a tool. A starting point. A piece of information among many. It is not a basis for installing an unstudied product on an elementary school playing surface without further analysis.
Ralston’s second written admission: elementary children are not the studied population
On the same day, in the same exchange, Ralston made an even more consequential concession. In a March 25, 2026 email, in reference to OEHHA’s research population, Ralston acknowledged in writing that elementary-age children are “closer to the ground” than the populations evaluated by the study.
This is not a minor stylistic concession. It is a written acknowledgment of a fundamental scientific limitation.
The OEHHA study’s exposure modeling assumed certain breathing zones, certain hand-to-mouth contact patterns, certain skin contact durations, and certain body geometries that reflected the populations it studied — predominantly adolescent and adult athletes on synthetic turf athletic fields. Elementary school children, who sit on playing surfaces, lie on them, roll on them, and put their hands in their mouths throughout the school day, occupy a different exposure environment.
Ralston himself acknowledged this in writing. OEHHA’s own staff scientist confirmed it in panel testimony.
That admission, by itself, disqualifies the OEHHA study as a basis for clearing an elementary school installation.
Ralston’s third written admission: there is no government health study for this product
In the same March 25 exchange, Ralston confirmed that no government health study exists specifically for the PureSelect Olive infill being installed.
The district’s UCP complaint record and CEQA Demand Letter both document this fact, drawn directly from his own written communications: “The OEHHA study was conducted on crumb rubber, not olive infill. No government health study exists for PureSelect Olive infill specifically.”
This is the foundation of the entire safety argument the district has offered to parents:
- A study of crumb rubber, not the product being installed.
- A study population that does not match elementary-age children, as Ralston himself conceded and OEHHA’s own staff confirmed.
- An admission, in writing, that the study has limitations.
- An admission, in writing, that no government health study covers the actual product.
- OEHHA’s own published acknowledgment that the study did not assess the synthetic carpet, microplastic degradation, or environmental runoff.
- A Scientific Advisory Panel record showing OEHHA did not adequately model heavy-use exposure for children at all.
This is not a misreading of the district’s position by concerned parents. This is the district’s own facilities administrator, OEHHA itself, and OEHHA’s own scientific review panel — all on the written record — telling the same story: this study cannot do the work the district is asking it to do.
What the district has used instead of an actual study
In the absence of a study that covers the product or the population, the district has substituted three things:
FieldTurf’s marketing claims. FieldTurf’s own product literature describes PureSelect as tested to the EN-71-3 European Toy Testing standard. EN-71-3 is a chemical migration standard for children’s toys. It is not a human health exposure standard for children spending hours daily on a 60,000-square-foot playing surface in Sacramento heat. It is the wrong test, applied to the wrong product use, marketed as if it were the right one.
The absence of complaints from JFK High School. On April 8, 2026, Ralston wrote that the absence of complaints from students at “the site currently using olive pit infill” supports the safety of the installation. That site is JFK High School, with students aged 14 to 18, installed less than a year before. As discussed elsewhere on this site, an adolescent population at a high school athletic field is not a substitute for elementary-age children at recess. Ralston himself conceded the age difference matters.
Ralston’s personal experience. Across multiple emails, Ralston has cited his “25 years experience dealing with playing surfaces at the professional and school age level” as the basis for the decision. Personal experience is not a medical assessment. Groundskeeping experience, however extensive, is not pediatric environmental health expertise.
When you remove the OEHHA study, the toy-migration standard, the JFK precedent, and Ralston’s personal experience — each of which fails on its own terms — what remains as the medical basis for installing this product on 600 elementary children?
Nothing remains. There is no remaining basis.
What the district acknowledged but did not act on
This is the most important part. The district’s own facilities administrator did not deny these limitations when parents raised them. He acknowledged them. He conceded them. He put them in writing.
OEHHA itself, in its own published report, has acknowledged the study did not cover the synthetic carpet, did not assess microplastic degradation, and did not address environmental runoff.
OEHHA’s own Scientific Advisory Panel, in its own meeting record, raised methodological concerns about how the study modeled heavy-use exposure for children.
And the district has proceeded with the project anyway.
That is the conduct the Sacramento City Unified School District Board of Education needs to evaluate. Not whether the OEHHA study is a useful resource — it can be — but whether a study with limitations openly acknowledged by its own authors, applied to a different product, used for a different population than it studied, is a legally and ethically sufficient basis for installing an unstudied surface on a school full of young children.
The district’s own answer, judging by Ralston’s actions, is yes.
The Board has the authority to give a different answer. It can pause the project, require an independent pediatric health review, and direct staff to install natural grass with proper drainage and irrigation. The funding is allocated. Construction has not yet begun.
Your email is what makes the Board ask the question Ralston has avoided: if the only health study you cited doesn’t cover the product or the children, and the study’s own authors acknowledge its limits, what study does?