Seeing with alarm young soccer goalies she’d coached contracting lymphatic cancer, a University of Washington coach, Amy Griffin, was concerned that this might be more than a coincidence. She hadn’t experienced such a devastation in her previous years of coaching and wondered if it had something to do with the crumb-rubber playing surface that the stricken goalies voiced suspicions about.

She began to compile a list in 2009 of those afflicted. Her list has continued to grow: Julie Foudy reported in November 2015 that Griffin’s latest number of victims stood at 200 athletes. At least 15 have now died. All had played on synthetic turf. These included 158 soccer players, of whom 101 were goalies, and 80 of the 200 had lymphomas. Most are younger than 30.

David Brown, formerly with the Centers for Disease Control and now toxicologist with Environment and Human Health Inc. (a company that promotes ecological strategies for development), says that the atypically large number of lymphomas in this group – when leukemias are and have been the more common cancer among this age group – suggest that a new environmental factor is involved, and that the factor is likely chemical.

The studies claiming crumb rubber is safe for playing fields were mostly of short duration – speculative, lab-limited studies with few samplings, done before crumb-rubber fields were in wide use, and they include no studies of actual human groups potentially affected. So, to date, nothing has proved that tire or other rubber infill isn’t safe, but nothing has proved that it is, and the anecdotal evidence above suggests that at least some tire-rubber fields may be deadly. (New York City and Newark, N.J., each closed one field for having lead levels three times the federal indoor air standard.)

Italy banned crumb-rubber infill as early as 2005. The Trust for Public Lands in New York City ceased using crumb infill for playgrounds in 2008. Bowen Island, B.C., and Riverdale High School in New York City opted for all-organic-infill by 2009, and both the New York City Parks Department and the Los Angeles Unified School District have stopped using crumb-rubber infill for all new fields. The Los Angeles Unified School District removed the crumb-rubber infill from 54 pre-schools and sued two of the installers, settling out of court.

Other communities, such as San Carlos and Long Beach, Calif., Pleasantville, N.Y., and Gaithersburg, Md., have chosen all-organic-infill for their fields. Finally, Montgomery County, Md. (adjacent to Washington, D.C.), after assessing data, between 2011 and 2015, from their own field maintenance staff (evaluating an existing all-natural field), the manufacturer, and a consulting firm, and after considering all the known potential drawbacks to the kind of playing field that they ultimately chose, decided in 2015 to approve “only the use of plant-derived infill” for new fields.

The above information is from readily available Internet sources.