University of Washington soccer coach Amy Griffin has compiled a list of more than 180 young athletes being treated for cancer.

Many of them have lymphoma. More than half are soccer goalies.

Griffin thinks this is no coincidence.

Her concerns are highlighted in an ESPN documentary “Turf Wars.”

In the documentary, Griffin and former U.S. National Team midfielder turned ESPN reporter Julie Foudy point to one possible connection among all those players who’ve contracted cancer  artificial turf made with crumb rubber.

Crumb rubber is made from recycled car and truck tires that are ground up into small pieces and spread on fields to give them more bounce.  

The artificial turf can break down into smaller particles during use. These pieces can end up in the eyes, mouths, and open wounds of athletes  or anyone using the field.

Soccer goalies, who spend a lot of time diving and catching balls on the ground, may have a higher level of exposure.

“A lot of us could have ingested those things so easily and it does make me mad,” Andrea Laymon, a former college-level soccer goalie, told Healthline.

“It’s bad enough that you find it all over the place when you’re walking,” she added, but it’s worse “if you’re ingesting it and it could be causing health concerns.”

Research Limited on Crumb Rubber

Linking Griffin’s list of athletes with cancer to the artificial turf will be challenging. So far, that research hasn’t been done.

“The concern has been over a number of athletes developing cancer — lymphomas, in particular — but I don’t think there’s been any solid epidemiological research that relates the two,” Dr. Arthur L. Frank, Ph.D., a professor in the Dornsife School of Public Health at Drexel University, said in an interview with Healthline.

Frank also notes that certain types of cancer  such as Hodgkin’s lymphoma  are not uncommon among young people and can have many causes.

The states of Washington and California have already announced plans for two new studies on the health effects of artificial turf. Two U.S. senators publicly called upon the Consumer Product Safety Commission this week to launch a federal investigation.

The artificial turf industry stands by the research that has been done to date.

"We've got 14 studies on our website that say we can find no negative health effects," Dr. Davis Lee, a board member of the Synthetic Turf Council, an industry group, told NBC News. "There's certainly a preponderance of evidence to this point that says, in fact, it is safe."

Artificial Turf More Than Just Rubber

Others, however, call into question the decision to turn old tires into the more than 12,000 artificial turf playing fields in the United States.

“You’re talking about putting a petroleum-based product out on these fields that kids are going to be running across, adults are going to be running across, and they’re going to fall down,” Steven G. Gilbert, Ph.D., DABT, director and founder of the Institute of Neurotoxicology and Neurological Disorders, told Healthline.

Tires also contain other compounds, some of which end up in crumb rubber.

“What we know is it’s a hazardous material,” said Gilbert. “Would you go out and spread crumb rubber on your front lawn?”

According to the nonprofit Environment and Human Health, Inc., crumb rubber can contain toxic and cancer-causing chemicals, including metals such as lead.

Laymon, along with other soccer players that she has talked to, are concerned that not all of the potential health issues associated with artificial turf were looked at earlier.

“We’re all a little upset,” said Laymon. “They’re putting this product out without trying to give it its proper due.”

Gilbert echoes her concerns but also says that more research is needed to look at small children’s exposure to crumb rubber.

Children can receive a larger dose of chemicals due to their small body size. They also play differently.

“Kids are not like adults,” said Gilbert. “Kids are down close to the surface of these fields. They’re down there falling down. They’re rolling around on this stuff.”

It may take some time before the results of the state’s studies are available. The long wait for definite answers may deter some users of artificial turf.

“Until you find out a little bit more about it,” said Laymon, “you definitely don’t want to be anywhere near it.”

However, Frank, whose work involves helping people minimize their exposure to things known to cause cancer, recommends reasonable caution.

“With this material,” he said, “the data is not all that strong that it would concern me about kids playing on this material at the present time.”

To minimize potential exposures, health officials recommend that people who use artificial turf fields wash their hands, clean open wounds, take a shower, and clean their equipment and clothing soon afterward. This is especially important to do before eating.