Crumb Rubber Artificial Turf

Crumb rubber artificial turf refers to a synthetic turf that is composed of materials made from recycled tires. This material is present in over 13,000 fields across the country, as well as on playgrounds. Concerns about crumb rubber artificial turf have focused on whether recycled tire crumbs may expose people to chemicals associated with tires, such as metals, volatile organic compounds, and others. Traditionally, public concern has also focused on whether users may face increased health complications from contact with or inhalation of crumb rubber pieces. The U.S. Environmental Protection Agency (EPA) Office of Research and Development (ORD), the Centers for Disease Control and Prevention (CDC), and the Agency for Toxic Substances and Disease Registry (ATSDR) have released both major parts of the Federal Research Action Plan on Recycled Tire Crumb used on Playing Fields and Playgrounds. Part 1 was released in 2019 and described what exactly is in tire crumb rubber. Part 2 was released in 2024 and described possible ways of exposure for users of synthetic turf fields with tire crumb rubber infill.

These reports should not be considered a complete safety evaluation, as the EPA states that neither study is a risk assessment. However, EPA adds that the study's findings support the conclusion that, even though chemicals are present in tire crumb rubber and exposures can occur, those exposures are likely minimal.

Background

The first documented use of synthetic turf dates back to AstroTurf in 1966. Since then, the use of artificial turf on soccer and other playing fields has advanced technologically and grown in popularity. Known for being a durable, low-maintenance, and cost-effective alternative to grass, crumb rubber artificial turf has been used in over 13,000 multi-use artificial turf fields across the country. The Synthetic Turf Council trade group estimates that there are approximately 12,000 to 19,000 full-size turf fields in the U.S. with new fields being installed at a rate of 1,200 to 1,500 per year.

There are several kinds of synthetic turf surfaces, with one of the most common types being artificial crumb rubber. This type of turf often uses synthetic fibers, manufactured to resemble natural grass as a base in conjunction with a synthetic infill material. These fibers are typically made from nylon, polypropylene, or polyethylene. The most commonly used base materials, or infill, are granulated crumb rubber, usually from recycled tires, flexible plastic pellets, sand, and rubber-coated sand. In many cases, a combination of sand and crumb rubber are often used. Crumb rubber is produced by grinding used tires. Steel and fiber tire components are removed during the process, and rubber pellets are produced in sizes ranging from about one-sixteenth to one-quarter inch in diameter. This crumb rubber infill is usually applied at a rate of two to three pounds per square foot of field surface. Crumb rubber artificial turf is much more popular than its natural and organic counterparts due to its long-lasting durability, low-maintenance requirements, and relatively low cost of installation and up-keep. Further, crumb rubber artificial turf is known to have a positive impact on the environment because it conserves water typically used for maintaining grass fields and eliminates the need for pesticides and fertilizers.

While crumb rubber artificial turf is extremely popular in the U.S., it has become much more controversial due to health and safety concerns. Most notably, in 2014, Amy Griffin, an associate women’s soccer coach at the University of Washington, compiled a list of soccer players with cancer after several goalkeepers in the area developed blood cancers around the same time. This list grew from 53 people in 2014 to 237 in 2016, sparking fear that a cancer cluster had developed in this region that was somehow associated with the crumb rubber turf being played on.

In response, the Washington State Department of Health launched a 2016 investigation into the seemingly high rates of cancer diagnoses being found in soccer players. The study was limited in scope and sought only to address the question of whether this specific group of soccer players was displaying higher rates of cancer than those expected in the general population. However, this was not a formal study. Rather, it was simply a statistical investigation into rates of cancer diagnoses in this specific population. The study did not include testing of any soccer fields and the results could not rule out with statistical certainty that some chemicals within crumb rubber turf can cause cancer. What the Department of Health did find was that this was not, in fact, a cancer cluster. Rather, they found that soccer players were actually receiving cancer diagnoses at a rate lower than what was expected in the general population.

Nevertheless, this case gained national attention, even prompting some states to put a moratorium on the installation of crumb rubber fields until there could be a greater sense of certainty on the safety of its use. The lack of a centralized and authoritative consensus on this issue became necessary. As a result, on February 12, 2016, the U.S. Environmental protection Agency, along with the Centers for Disease Control and Prevention and the Consumer Protection Safety Commission, launched a multi-agency Federal Research Action Plan on Recycled Crumb Used on Playing Fields and Playgrounds.

Federal Research Action Plan on Recycled Tire Crumb Used on Playing Fields and Playgrounds

EPA and CDC/ATSDR released the Part 1 Tire Crumb Rubber Characterization Research Report in 2019. As anticipated, the report discovered that a variety of metals, semi-volatile organic compounds, volatile organic compounds, and bacteria were detected in recycled tire crumb rubber infill. It also measured releases of organic chemicals from tire crumb rubber and the bio accessibility of metals through simulated ingestion and dermal exposure fluids.

EPA and CDC/ATSDR released Part 2, the Tire Crumb Rubber Exposure Characterization Report, in April 2024. Part 2 comprised field, personal, and biomarker sampling, as well as questionnaires and video-based activity assessments and exposure modeling. The study inspected how people may come in contact with tire crumb rubber while using synthetic turf fields.

For many chemicals measured during active play at outdoor fields, EPA found that air concentrations were not different from background samples, while certain chemicals, such as methyl isobutyl ketone, benzothiazole, 4-tert-butyl phenol, and several PAHs, were somewhat higher. EPA also discovered that numerous chemicals had higher concentrations in air samples at the indoor field compared with the outdoor fields.

EPA also stated that only very small fractions of metals were released from tire crumb rubber into simulated biological fluids, with an average mean release of around 3% in gastric fluid and less than 1% in saliva and sweat plus sebum. In the biomonitoring pilot study, EPA found that concentrations for metals measured in blood were similar to those in the general population, and no differences in PAH metabolites in urine were seen between participants using natural grass and participants using synthetic turf fields with tire crumb rubber infill.

EPA warned that the study was not designed, nor is it efficient by itself, to directly address concerns about potential health risks. Therefore, rather than using this study as proof that crumb rubber turf is harmless or dangerous, it should present federal research as important exposure-characterization data.

Injuries and Damages

Potential concerns associated with crumb rubber artificial turf include heat-related illness, skin abrasions, infections associated with open wounds, allergic reactions in sensitive individuals, and chemical exposure. New federal research confirms a more specific discussion of exposure. Studies found that tire crumb rubber contains chemicals that can be exposed through air, turf materials, field dust, and skin contact when playing. However, based on the measurements gathered, the EPA's overall finding for the study's playing-field section was that exposures are generally limited.

High surface temperatures of synthetic turf have been one of the few aspects of concern with comprehensive, supportive data. Synthetic turf fields absorb heat, resulting in surface temperatures that are much higher than the temperatures of the surrounding air. One study conducted at Penn State University took measurement of surface feet, finding that air temperatures reported at 79°, 78°, and 85° had corresponding surface temperatures of 120°, 130° and 146° F. A maximum surface temperature at Brigham Young University was recorded to be just over 200°F. The surface temperatures reported on synthetic turf fields can get high enough to reach levels of discomfort and may contribute to heat stress among field users. Users should be adequately warned about the potential risk and reminded to hydrate and take cover in shade when possible. Otherwise, users may put themselves at risk for heat stroke, exhaustion, cramps, or heat rashes.

Next, some people have expressed concern that infections, including methicillin-resistant Staphylococcus aureus (MRSA), echovirus, herpes simplex virus, hepatitis virus, and coxsackie virus, may be more common among users of synthetic turf fields rather than users of natural turf fields. However, it is possible that skin cuts and abrasions may result from contact with any athletic fields and that those cuts are susceptible to infection. In that case, athletes and other users should pay close attention to the development of skin abrasions and seal off the wound from any possible airborne or surface infection.

Further, about six percent of the general population is allergic to substances in latex, which can cause an allergic reaction in some cases. Tire rubber contains the latex allergen, although at a much lower level than in latex gloves and other similar items. People playing on synthetic turf may be exposed to latex allergens through direct contact with the field or through the inhalation of latex particles in the air. However, a study conducted by the California Environmental Protection agency tested samples of tire rubber on the skin of lab animals, to which none of the animals developed any rashes or allergic reaction from contact with the rubber.

Perhaps the largest area of concern when it comes to crumb rubber artificial turf is the potential for chemical exposure. Many are concerned that exposure to chemicals in the synthetic turf may be a cause for cancer in its users, and it is this exact concern that prompted the EPA to launch its multi-agency investigation into the issue.

Chemical exposure can occur through ingestion, inhalation, dermal, and ocular exposure. Tires are manufactured from natural and synthetic rubbers along with a multitude of other chemical additives. These chemical additives may include zinc, sulfur, carbon black, and oils containing polyaromatic hydrocarbons and other volatile organic chemicals. And since crumb rubber is manufactured from used tires, the turf contains the same chemical materials.

However, current research has not established a causal relationship between exposure to crumb rubber artificial turf and specific cancers or other diseases. EPA and CDC/ATSDR have released more findings through the Federal Research Action Plan on Recycled Tire Crumb Used on Playing Fields and Playgrounds. According to the agencies, tire crumb rubber contains chemicals, and exposure can happen in a number of ways.

Elevated lead levels found in certain older synthetic turf fibers in the mid-2000s were one of the biggest historical concerns. In response, the Agency for Toxic Substances and Disease Registry and the Centers for Disease Control and Prevention assessed the possibility of lead exposure, which led to changes in product standards and production procedures. PFAS, microplastics, disposal concerns, and the environmental effects of artificial turf systems have all received more regulatory attention in recent years.

Despite the concerns with crumb rubber artificial turf described above, many credible studies from governmental agencies have validated the safety of playing on turf. Specifically, in 2010, the California Office of Environmental Assessment determined that there are no bacteria in artificial turf that can cause public health concern.

Legislation and Regulation

In addition to crumb rubber, artificial turn systems in general have been the subject of recent lawsuits and regulations. In 2023, California passed SB 676, which made it clear that artificial turf and synthetic grass are not considered drought-tolerant landscaping. This gives local governments more power than previous California laws did to control or limit artificial turf.

AB 1423, which would have limited artificial turf with purposefully added PFAS, was also taken into consideration in California. However, the bill was vetoed in October 2023. Legislation that would limit state and local support for artificial turf fields with plastic, zinc, or purposefully added PFAS has been considered in Massachusetts.

The regulatory trend is best described as evolving. Earlier concerns focused heavily on crumb rubber infill, while newer trends more often address PFAS, plastic materials, zinc, environmental impacts, and disposal concerns associated with artificial turf systems generally.

One of the most important new problems with artificial grass systems is PFAS. Regulators and environmental organizations have been more concerned about possible contamination, disposal issues, and long-term environmental effects, even if PFAS may come from turf fibers, backing materials, or production methods rather than the actual crumb rubber filler. Artificial turf producers, facility owners, and insurers may come under more scrutiny as PFAS regulations spread throughout the United States.

Liability and Insurance

The 2024 EPA/CDC/ATSDR exposure data may be relevant to insurers' assessments of damages and causality in bodily injury claims. The results may also be relevant to defense strategy, field maintenance inquiries, underwriting, and risk selection. However, insurers should refrain from viewing the reports as a comprehensive answer to all possible health or environmental problems because the EPA emphasizes that the reports are not a risk assessment.

General liability, products liability, finished operations, environmental liability, pollution exclusions, public entity coverage, and contractor liability are some examples of coverage questions. Allegations of environmental pollution, runoff disposal, and PFAS can create different coverage challenges than those of traditional athletic injury claims.

To make sure that coverage corresponds with possible liability risks, facilities that own or run artificial turf fields should examine their current insurance plans. When assessing future risk exposures and coverage requirements, insurers and insureds should keep an eye on developments in environmental research, legislation, and court rulings since artificial turf rules and litigation are always changing.

The projected usable life of most artificial turf fields is between eight and twelve years. Owners must take into account recycling possibilities, disposal expenses, and changing environmental regulations as fields get older. Future regulations pertaining to PFAS, microplastics, and landfill disposal may raise the cost of replacement and remediation for governments, schools, and facility owners, raising further liability and insurance concerns.

Litigation

Exposure litigation is still unclear. Because the EPA's exposure results were generally restricted and the reports are not a risk assessment, the federal study may make some toxic-exposure claims more difficult to verify. Nonetheless, responsibility, product liability, failure to warn, construction flaw, contract, environmental pollution, or public procurement theories may still give rise to artificial turf claims.

In addition to cancer and exposure to crumb rubber, additional concerns that may be the focus of claims include heat-related injuries, field maintenance, drainage, surface flaws, PFAS accusations, disposal requirements, or statements made during installation and sale. Artificial turf litigation is still developing, despite the fact that relatively few cases involving crumb rubber exposure have led to significant rulings.

Future Outlook

The composition of tire crumb rubber and its exposure pathways have been thoroughly documented by federal research. The most reasonable conclusion is that, although exposures can happen, and chemicals are found in recycled tire crumb rubber, the EPA's playing-field data typically shows minimal exposure under the conditions examined.

However, the EPA asserts that the reports do not constitute a risk assessment and are insufficient on their own to properly address every topic about health risks. Stakeholders should thus keep an eye on advancements in science, regulations, product modifications, PFAS limitations, heat problems, disposal requirements, lawsuit patterns, and insurance coverage challenges.

Documentation, informed procurement, maintenance procedures, heat protocols, contractual risk transfer, product specifications, and insurance coverage evaluation should be the key priorities for schools, towns, facility owners, manufacturers, contractors, and insurers.