Everything from tires to old shoes to wine-cork rubber are under consideration.

The Bainbridge School District is moving ahead with plans for an artificial field at Memorial Stadium. But the district is still considering its options when it comes to the type of turf selected.

Four varieties of infill – the loose crumbs used as padding between blades of synthetic grass – will be considered as the project rolls into the environmental review and permitting phase.

District Capital Projects Director Tamela VanWinkle said the district has made a determination of environmental non-significance for the stadium renovation project. It will be opened to a two-week public comment period beginning Monday.

Still an option is recycled tire rubber infill, which was the subject of intense public scrutiny leading up to the school board’s decision to approve an artificial surface. It will be considered alongside three other infill types: Nike Grind, Terra XPS and Ethylene Propylene Dien Polimerisat rubber.

“What we wanted to do was leave our options open while we continued to evaluate cost,” VanWinkle said.

The allure of tire crumb rubber is mostly in the price tag; other synthetic infill options could raise the project cost by more than $100,000.

But rubber crumbs have been the subject of local and national debate over health and environmental impacts both locally and nationally, with dueling studies over the possibility of toxins leaching into players and the environment.

While other infill options aren’t as well studied, there is an assumption that the purer ingredients would contain fewer chemicals than old tires, said Jeff Burke of D.A. Hogan, the district’s consultant for the project.

Nike Grind is made from the ground-up soles of old shoes and usually mixed with other infills, Burke said.

Terra XPS uses cylindrical pellets made of a polymer plastic, the same material used to make synthetic wine corks. It has only been on the market for two years and is used primarily in Europe. EPDP is a manufactured rubber available in several colors.

An unknown factor is how these materials will be dealt with after the field wears out, and how much will end up in landfills.

“We’re just coming up on the period where some of these infill fields are being replaced,” Burke said. “It’s hard to say what opportunities there are for recycling right now.”

Meanwhile a Park District proposal for synthetic turf at Battle Point Park is sticking with crumb rubber infill as its only option, a city planner said.

Opponents of artificial fields are continuing a signature drive for a voter initiative that would block synthetic field construction on the island and levy a tax to support natural fields.

Volunteers have collected signatures aboard ferries and at Saturday’s political caucuses.

Chris Van Dyk, who leads the effort, said the district had not been objective in analyzing the risks of plastic turf.

“Given the health and environmental information that is out there, it is a case of hear-no-evil, see-no-evil and know-no-evil for the school district to declare non-significance,” he said. “The district truly has its head in the sand.”

Natural grass should be at least be considered as an option alongside artificial turf as an option, Van Dyk said.

“We want a public debate, we want the public to weigh in with a vote, and if they pick artificial turf, then so be it,” he said.