Proponents of the artificial grass sports fields that have been springing up all over San Francisco in recent years are hoping that a state study will put to rest concerns over the fields' safety, though some critics remain unconvinced.
The study, released in October, was undertaken more than two years ago amid increasing concerns that the fields - made of old tires ground into small pellets and plastic blades that mimic real grass - could pose a public health risk. Critics were worried that the fields harbor dangerous bacteria that would lead to more skin infections and could release toxic chemicals into the air, particularly when temperatures rise.
The state's study concluded that there are actually fewer bacteria on synthetic turf fields compared with natural grass. State researchers did find some "volatile organic compounds" - such as lead and other heavy metals - in the air near the artificial grass fields, but the presence of these toxins was so low that no public health concern was identified. And, because there was no relation between the surface temperature and the concentrations of those chemicals, the study's author said there is no reason to recommend that field usage be limited when it's hot.
