Recent concerns over the safety of artificial turf fields has raised debate and speculation for a handful of soccer players across the country being diagnosed with cancers such as non-Hodgkin lymphoma. University of Washington women's soccer coach, Amy Griffin has been gathering evidence to see if the small black pellets found among artificial turf may be causing serious health problems for soccer players, specifically goal keepers. The crumb rubber used to support turf structure is made from shredded tires and can often be seen collecting among parts of turf fields, and in athlete's shoes and clothes. Tires are made of an assortment of synthetic petroleum-based chemicals, four of which are listed as carcinogenic (arsenic, benzene, cadmium, and nickel). Griffin noticed a coincidence in cancer diagnosis among goal keepers after soccer fields switched from grass to artificial turf. While there have only been 38 listed cases throughout the United States, the safety of artificial turf and it's crumb rubber components is still up for debate.