Carrie Levin is a Sunnyvale resident and passionate advocate against synthetic turf.
"I care because this stuff works its way in the storm drains and these storm drains go to the bay and the water in the bay end up in our drinking water and marine life and habitat so it's affecting it," Levin said.
The Fremont Union High School District has five high schools that already have synthetic fields.
On Tuesday, the District's Board of Trustees unanimously approved upgrading three of those fields with newer synthetic turf instead of reverting back to grass.
Instead of recycled tires and rubber - the infill will be olive pits.
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Superintendent Graham Clark said they surveyed coaches and students who prefer the synthetic turf.
"They also like it that we don't have issue with geese or with mud and things like that so it's very playable," Clark said.
He also mentioned the amount of use their fields get.
"We put more demand on them than most parks have on their fields actually more than most college sports on their fields," Clark said. "And even more than professional teams because usually, a professional team doesn't have as many groups playing on their fields as we do."
Concerns regarding how hot turf can get were discussed.
"I call it the old turf, they took readings it was a 139 on Monday, and 145 today. And in the new turf it was about ten degrees cooler so 132, 135," Clark said. "So that's a difference between the rubber and the olive pit infills, regular grass on those days was in the mid-90s."
ABC7 News heard from Alice Kaufman with the nonprofit Green Foothills.
"As we experience more and more extreme heat events, there's going to be more and more days where these fields are not going to be usable," Kaufman said.
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This past Spring, the Santa Clara County Board of Supervisors voted to study a potential ban on artificial turf on county-owned property.
Last year Governor Gavin Newsom signed a new law that allows local governments to ban artificial turf.
"Millbrae for example has done that and a city in Southern California San Marino has also banned it," Levin said.
Levin expects more regulation is coming, along with more information about the potential health impacts of plastic turf.
"We tend to look at the research by universities and outside third-party labs, the data that's coming in and we're not paid to do this we're just so concerned that the amount of data out there is a cry for alarm," Levin said.
Clark said construction for the replacement of the turf will begin in summer next year at Cupertino High School and Monte Vista High School. Construction at Lynbrook High School is set for 2026.