Bill, John, and Bob Fisher founded and partially funded City Fields Foundation "to give back to the city and provide children with access to the same fields and opportunities they had as children," Hannan said.
Opponents argue that synthetic fields are not the same ones the Fishers played on as children. In January 2008, Pinky Kushner of the Sierra Club sent a letter asking the Recreation and Park Department to suspend the program until "it can be demonstrated that these projects will have no negative impacts on the environment or on human health and enjoyment of public open space."
Her letter references the city's Precautionary Principle, a policy whereby the city seeks to avoid taking action that might harm the environment even when there is a "lack of full scientific certainty about cause and effect." SF's Environment Deparment says the principle "does not advocate the avoidance of any and all potential environmental risks." Rather, it "advocates for a public process in which the benefits of an action or technology are weighed against potential risks."
Rec-Park and City Fields are confident the Synthetic Playfields Task Force inquiry meets the requirements. But Sup. Ross Mirkarimi has authored a resolution asking for a moratorium on turf conversion until the state completes a study on the issue. Gov. Arnold Schwarzenegger signed legislation in September 2008 tasking state agencies to study the turf question and submit a report by September 2010.
Even if it passes, Mirkarimi's resolution is nonbinding and unlikely to halt the current conversion of Kimbell Field. But it does have support from activists who believe synthetic turf poses a health risk. In several parks, community members lobbied against the proposed conversions and successfully convinced City Fields and Rec and Park not to move forward.
Franco Mancini, president of Friends of McLaren Park, described how a few residents were initially opposed to the proposed fences and lighting but soon became embroiled in the larger issue of synthetic turf and "playing Russian roulette with our children's safety."
The new synthetic turf consists of a polypropylene fabric backing, an infill of crumb rubber made from shredded tires, and polyethylene fibers that replicate blades of grass. One of the principal concerns is that the crumb rubber infill, made from up to 50,000 tires per field, contains hazardous materials that pose potential health risks. Other health concerns are the presence of lead as a color fixative and the possibility of zinc leaching into the groundwater.
There are also concerns about what to do with the fields when they wear out and whether particles leach into the environment, problems Rec and Park officials have promised to work with turf companies to address. But so far research into the environmental impacts of turf have yielded conflicting results.
Resident Kelley Watts is concerned the "research is only in the very beginning stages" and compares the situation to the 1940s and '50s when conflicting research about cigarettes was emerging.
Concerns that turf overheats on hot days led to ongoing moratoriums in Los Angeles and New York City. San Francisco's mild climate doesn't create the same problem, although it does have the underlying issue that synthetic turf absorbs heat and replaces carbon-absorbing grass, contributing to what is known as the "heat-island effect," a factor in global warming.
The Athena Institute, an Ontario, Canada, nonprofit, estimates that for the average synthetic soccer field to be carbon-neutral, 1,861 trees would have to be planted and allowed to grow for 10 years.
Kimball Field is in the process of converting but the next project, and potential fight, will be at Golden Gate Park's Beach Chalet soccer fields next year.