Synthetic Turf Council on crumb rubber and athletic fields

This piece opens with a statement from STC, followed by an edited version of an article by Megan Quinn that originally ran earlier this year in the March-April edition of Scrap, a publication of the Institute of Scrap Recycling Industries, with their permission.

Statement from STC

“We welcome the [federal study] announcement of this multi-agency effort and look forward to coordinating with the agencies as well as other stakeholders as this research action plan moves forward.

“We have consistently said that we support all additional research. At the same time, we strongly reaffirm that the existing studies clearly show that artificial turf fields and playgrounds with crumb rubber infill are safe and have no link to any health issues. The current body of research is comprised of dozens of reports, including peer-reviewed academic studies and federal and state government analyses.

“It’s also important to note that when we talk about crumb rubber infill in synthetic turf, we are also talking about the same recycled rubber that is used in a variety of products that are widely considered to be safe, such as sneakers, garden hoses, hospital floors, surgical gloves, and an array of other uses.

“We hope the federal government’s involvement, which we have been encouraging for years, will settle this matter once and for all, put parents’ minds at ease, and validate past and recent due diligence by public officials.”


In North America, about 98% of synthetic turf fields use granulated recycled tire rubber, or crumb rubber, as infill. The granules fill in the space between synthetic blades of grass to provide cushioning, aid drainage, and help prevent injuries when athletes run, slide, or take a tumble. Yet even as these fields become more common, some community members have raised questions about whether crumb rubber is safe.

On one side of the conflict are more than 70 studies and literature reviews from state health departments, universities, and other independent entities in the United States and in Europe. None of the studies say crumb rubber is a public health or environmental concern. On the other side are environmental groups and residents who worry that various chemicals in tire rubber could cause cancer or other health problems, and they are asking school boards, cities, and states to ban crumb rubber infill. Tire processors and synthetic turf vendors are concerned that this fear has trumped the facts and maligned a product with real environmental benefits.

Over the years, numerous organizations have looked into crumb rubber’s potential health and environmental risks. Studies have examined several factors, such as how crumb rubber affects the human body when it is ingested or when athletes’ skin comes in contact with the crumbs. Other research has considered whether crumb rubber releases harmful levels of chemicals into the air. None of the studies have found evidence that the material is harmful.

A 2013 study by researchers at the Rutgers Robert Wood Johnson Medical School in New Jersey evaluated opportunities for exposure to trace metals, semi-volatile organic compounds, and polycyclic aromatic hydrocarbons from crumb rubber infill and the artificial turf fibers. Researchers measured these factors in simulated body fluids representing digestive fluids, lung fluids, and sweat. The researchers found that PAHs were routinely below detection limits, and SVOCs that have environmental regulatory limits were at levels too low to quantify. Some metals were detected, but researchers said the concentrations were low and likely would not cause health problems. “The study demonstrated that for the products and fields we tested, exposure to infill and artificial turf was generally considered de minimus,” it stated.

In 2009, four Connecticut state agencies (University of Connecticut Health Center, the Connecticut Agricultural Experiment Station, the Department of Public Health, and the Department of Environmental Protection) evaluated the health and environmental impacts associated with crumb rubber turf fields in Connecticut. Researchers looked at four outdoor fields and one indoor field, asking three soccer players at each field to wear personal monitoring devices to collect samples. The study tested about 200 chemicals at each field. Researchers concluded that there were no elevated health risks from playing on the indoor and outdoor fields, but they noted that indoor fields may need ventilation because of higher levels of chemicals at the one indoor field they tested. The Connecticut Academy of Science and Engineering peer-reviewed the findings.

In 2013, ChemRisk conducted a literature review for the Rubber Manufacturers Association to evaluate the health and ecological risks associated with the use of recycled tire rubber on playgrounds and athletic fields. While some of the ingredients used in tire manufacturing are considered to be “potentially hazardous to human health at high doses, the potential for athlete or child exposure to these chemicals is very low” when playing on a synthetic turf field, the study says. It notes that heating during the tire manufacturing process causes physical and chemical reactions that bond potentially harmful chemicals into the material, and “the process is designed so the release of chemicals into the environment is inhibited.” After reviewing research from both advocates and opponents of crumb rubber, ChemRisk concludes that “no adverse human health or ecological health effects are likely to result from [the] beneficial reuses of tire materials,” but it adds that additional scientific studies will help supplement and confirm the studies that have already been done.

More studies in the works

The US Environmental Protection Agency did a study in 2008 about synthetic turf fields, but officials say it was to test a method for measuring possible emissions from synthetic turf, not to determine possible health risks. The EPA says it “supports more comprehensive efforts to identify potential exposures to tire crumbs and better assess risks,” and it announced in February that it would participate in a joint study with the Centers for Disease Control and Prevention and the Consumer Product Safety Commission to further study possible health risks related to crumb rubber used on turf fields. The study aims to identify gaps in the current knowledge, characterize chemical compounds found in crumb rubber, evaluate possible risks, and involve stakeholders such as parents, athletes, and coaches, the EPA says. The agencies say they will have the first status report on the study by the end of 2016.

Al Garver, president of the Synthetic Turf Council, says STC supports the calls for more scientific studies and tests. The council worked with researchers from OEHHA’s study to help identify locations of several hundred fields throughout California. “The more it’s studied, the more it will validate the fact that the rubber is inert,” he says.

Crumbs of concern

Despite the scientific evidence to date saying crumb rubber does not pose health or environmental concerns, some communities have opted to ban or avoid crumb rubber infill for turf fields out of caution, saying future studies still could uncover dangerous effects.

Recyclers and rubber manufacturers feel science is on their side and the crumb rubber fears are unfounded. More than 70 independent, peer-reviewed studies done over the past 22 years have offered enough evidence to clear crumb rubber’s name, says ISRI President Robin Wiener. “These studies have pointed to the conclusion there is no indication of negative health effects tied to crumb rubber’s use in artificial turf” based on the current information, she wrote in an Oct. 27, 2015, letter to EPA Administrator Gina McCarthy. The letter asked the EPA to respond to the public’s concerns by highlighting the research, including the EPA’s own studies.

The concern has spread to places like Edmonds, WA, which voted in December to put an 18-month moratorium on installing any new synthetic turf fields made with crumb rubber infill from recycled tires. The city council enacted the moratorium after residents protested the local school district’s plans to take out the aging grass field at a school campus and replace it with synthetic turf. Patrick Doherty, the city’s economic development and community services director, says field construction was already underway when residents learned the new field would have crumb rubber infill, so workers completed the project before protests could halt construction. Because of the community outcry, he says, other fields that were scheduled to get similar upgrades won’t see that happen, at least during the 18-month moratorium.

Mark Rannie, vice president of Emanuel Tire (Baltimore), also believes the concerns come more from fear than facts. As chair of ISRI’s Tire and Rubber Division, he has followed the issue closely. Though he says communities and organizations have a right to decide whether to use crumb rubber or an alternative on their fields, he wishes people would read the studies to help them make the decision instead of discounting crumb rubber because other communities have concerns. “We just want the truth out there, crumb rubber is not problematic, according to the studies,” he says. “If a state agency or government agencies decide to declare a moratorium based on [fear], they are basing it on a political cause, not a scientific one.”

Rannie doesn’t expect future studies to indicate health risks, but he says the tire-recycling sector welcomes the research. More information and research can help inform the public and show that there’s nothing to fear, he says. And, in the unlikely event of a problem, he says, tire recyclers have to step up and be part of the solution. “You have to put health over business,” he says.

Those following the crumb rubber debate know it is far from over. Results from the California study may help Edmonds decide how to move forward with new field construction, but it may not be enough to sway worried residents, he says. And in Baltimore, Rannie acknowledges that it may take much more time—and many more conversations with worried customers—before the matter of synthetic turf is settled. Between now and then, many more soccer, baseball, and lacrosse games will go on, but “the best outcome is having the truth, having the evidence, and having those facts listened to,” he says.