September 13, 2023
The debate on whether grass or artificial turf better serves athletes has been ongoing since the 1960s when artificial turf was first invented by James M. Faria and Robert T. Wright at Monsanto. Initially sold under the name ‘ChemGrass,’ it was installed at the Houston Astrodome stadium in 1966 after lighting problems related to the new dome caused the stadium’s natural grass field to wither and die. ChemGrass’s success at the Astrodome led Monsanto to rebrand it to ‘AstroTurf’.
This artificial turf received praise because of its durability and resistance to rain and inclement weather, which are often disruptive in traditional grass fields. But Leo Durocher, renowned infielder, and legendary manager and coach wasn’t impressed. “If baseball was meant to be played on that rubber mat, I’m crazy,” he quipped. “Imagine that – a $45 million ballpark and a 10-cent infield.”
Today, artificial turf is ubiquitous across sports grounds, school and college fields, residential lawns, public parks, rooftop gardens, and even indoor play and recreational areas. According to one estimate, there are about 16,000 synthetic turf fields in North America, with as many as 1,500 installed annually.
However, a growing chorus of athletes, former athletes, mothers, scientists, and environmentalists is voicing concerns about artificial turf. They are alarmed by its impact on players' well-being, including the heightened risk of injuries and potential health hazards that arise after prolonged exposure, as well as its devastating effects on the environment.
As concerns about artificial turf grow, it's vital to understand how its components affect players and the environment.
Comprising plastic grass blades forming 'tufts', a backing material, adhesive, and supplemented by ground rubber or sand infill, artificial turf's structure plays a crucial role in player experiences and associated risks.
Players have reported a range of issues, including discomfort from the heat (with synthetic turf temperatures often 20-30°C hotter than natural grass surfaces), frequent abrasive burns leading to a 7-fold increase in MRSA infection risk compared to players without abrasions, increased strain on knees and joints due to the ground's hardness, and severe non-contact injuries often caused by cleats getting trapped in the artificial turf filaments. These concerns have gained traction in recent years, and they are just some of the problems players face. Others relate to health risks associated with toxins found in artificial turf and the commonly used crumb rubber infill.
In this blog, we delve into the ongoing debate surrounding natural grass versus artificial turf for sports surfaces. While artificial turf is hailed for its durability and convenience, we examine a range of concerns that cast doubt on its suitability for both human well-being and the environment. Our discussion explores the advantages of natural grass, including player safety and environmental impact, and also dispels the misconception that artificial turf is low maintenance.
We recognize that statistics and studies can be selectively employed to support either side of the argument. However, we contend that evidence from scientific research, insights from those who have actually played on these surfaces over the decades, and environmental considerations collectively support the conclusion that artificial turf tends to cause more injuries, is more taxing on the body, can cause serious health risks due to prolonged use, and ultimately, upon disposal, can contaminate our soil and water.
The complaints from players started almost as soon as synthetic grass was installed at the Houston Astrodome in 1966. New Orleans Saints’ defensive tackle Dave Long made a series of complaints against the Astrodome’s new playing surface. He described the field as being the “worst he’d ever seen” and as unyielding as linoleum, causing players to stumble over its uneven terrain. Gale Sayers blamed AstroTurf for his delayed comeback from off-season knee surgery. "This stuff will shorten careers,” Sayers was quoted as saying.
In 1976, the NFL Players Association or NLFPA urged the US Consumer Product Safety Commission to study whether Astroturf and other artificial playing surfaces posed an unnecessary safety risk. But the appeal fell on deaf ears.
Almost 44 years later, in September 2020, NFLPA president JC Tretter urged the NFL to “proactively change all field surfaces to natural grass”. Two years later, Tretter called for an immediate ban specifically on slit film turf, saying that the playing surface of this specific turf had statistically higher in-game injury rates compared to all other surfaces for non-contact injuries, missed time injuries, lower extremity injuries and foot and ankle injuries. “The injuries on slit film are completely avoidable — both the NFL and NFLPA experts agree on the data — and yet the NFL will not protect players from a subpar surface,” the statement said.
In April 2023, the NFLPA issued a strong statement in which it alleged that the NFL manipulated past injury data in order to bolster its claim that artificial turf fields were safe. Tretter discussed this matter in his article titled Why the NFL's Approach to Field Surfaces is Uneven.
A comprehensive study published in the American Journal of Sports Medicine in 2019, found significant differences in injury rates between synthetic and natural turf surfaces among elite NFL athletes. Analyzing data from all 1,280 NFL regular season games played between 2012 and 2016, with 555 on synthetic turf and 725 on natural grass, researchers identified 4,801 lower body injuries affecting 2,032 NFL players.
The results present a compelling case against synthetic turf. Players who participated on synthetic turf faced a 16% higher injury rate per play in comparison to those on natural grass. Moreover, the study found if the injury rate on natural turf was applied to the games played on synthetic turf, 319 fewer lower extremity injuries would be expected. The researchers' findings provided support for the distinction between synthetic turf and natural grass in their capacity to form divots that release cleats from the surface. The absence of such a shoe-surface release mechanism on synthetic turf emerged as a crucial factor contributing to the increased risk of injuries on that surface. This association remained consistent across various injury categories, including knee and ankle/foot injuries.
Particularly noteworthy were non contact/surface contact injuries, where a significant increase was observed in ankle and foot injuries, resulting in an average of 8 days missed from football participation. The risk of all lower extremity injuries on synthetic turf was found to be 27% higher compared to natural grass. For knee injuries, the risk increased by 46%, while for ankle and foot injuries, it rose to 68%. Notably, injuries causing an 8-day absence from football activity saw the risk of ankle and foot injuries on synthetic turf soaring to 103% higher than natural grass. In essence, the study's findings suggest that playing on synthetic turf is associated with a significantly elevated risk of lower extremity injuries, particularly non contact/surface contact injuries close to the playing surface.
This study is extremely significant because it uses the league's own internal injury data.
It isn’t just the NFL.
Another study published in the American Journal of Sports Medicine in 2019, which centered on college football governed by the National Collegiate Athletic Association or NCAA, established that artificial turf represented a significant risk factor for distinct knee ligament injuries in NCAA football.
Analyzing a vast dataset of 3,009,205 athlete exposures and 2,460 knee injuries from 2004 to 2014, the study shed light on specific knee ligament injuries that occur at significantly higher rates on artificial turf. These injuries included 1,389 MCL, 522 ACL, 269 lateral meniscal, 164 medial meniscal, and 116 PCL injuries.
One notable finding was that athletes encountered all types of knee injuries more frequently during competitions compared to practices. Athletes competing on artificial turf experienced PCL injuries at a staggering rate of 2.94 times higher than those playing on natural grass. This risk disparity was even more pronounced when competition levels were taken into account. Division I athletes competing on artificial turf faced PCL injuries at a rate 2.99 times higher than those on grass. Lower NCAA divisions (II and III) displayed a 1.63 times higher rate of ACL injuries and a staggering 3.13 times higher rate of PCL injuries on artificial turf during competitions compared to natural grass.
The study's conclusion is unequivocal: artificial turf presents a substantial risk factor for specific knee ligament injuries in NCAA football. The data clearly indicate that injury rates for PCL tears were significantly elevated during competitions on artificial turf compared to natural grass. This heightened risk was consistent across lower NCAA divisions as well. These findings further underscore the complex dynamics at play when athletes compete on artificial turf, raising concerns about the surface’s impact on player health and safety.
The challenges to athletes' health and safety extends beyond injury concerns. The surface temperature of artificial turf is significantly higher than natural grass.
A 1971 report said: “Players and coaches together complained – louder now – of the heat. Temperatures were 30° higher on synthetic surfaces. A New York Jet said he was ‘well done, cooked from the bottom up’ after the game in Miami where the Poly-Turf registered over 120° at 2 pm. In San Francisco Kermit Alexander of the Rams wrapped his feet in tinfoil ‘to play in the oven’.”
Recent research aligns with these historical grievances.
A 2002 study conducted at Brigham Young University found that the surface temperature of synthetic turf was a striking 37°F (20.6°C) higher than asphalt and a scorching 86.5°F (30.3°C) hotter than natural turf. Artificial turf frequently registers temperatures that range between 35° and 55°F (20° and 30°C) above those of natural grass, according to the Penn State University's Center for Sports Surface Research.
The contrast with synthetic turf is stark. Temperatures exceeding 100°F (38°C) are rare on natural grass, which typically ranges from 75° to 95°F (25° to 35°C) on a hot day and tends to remain cooler than the surrounding air. The reason is simple: natural grass blades transpire or release water vapor. And this evaporation causes cooling.
High temperatures on artificial turf can pose significant risks to players, affecting both their performance and well-being. Excessive heat can lead to heat-related illnesses, dehydration, and reduced physical endurance, ultimately hampering players' ability to perform at their best. The scorching surface temperatures of artificial turf can contribute to discomfort, increasing the likelihood of skin abrasions and burns, which can become entry points for infections like MRSA. Prolonged exposure to elevated temperatures may also elevate the risk of heat stress and heat stroke, potentially putting players' health and safety in jeopardy.
If the high temperatures on artificial turf aren't worrisome enough, there's another crucial aspect to consider when examining the health and safety impacts of artificial turf: bacteria.
Different types of bacteria play a significant role in both natural grass and artificial turf settings. Beneficial microorganisms present in the soil of natural grass fields help sanitize the surface by decomposing bodily fluids, animal waste, and algae. Artificial turf lacks these natural cleaning agents, leading to the requirement of artificial cleaning agents that need to be rinsed out to maintain a safe playing surface.
But that is not all. Unlike natural soil, the infill of artificial turf has reduced microbiological activity, creating an environment where harmful bacteria can thrive unchallenged by the beneficial microbes that typically flourish in natural turfgrass root zones. This imbalance raises the risk of potential infections to a concerning level.
This microbiological imbalance is related to another significant concern: the heightened risk of infections due to turf abrasions, particularly concerning drug-resistant bacteria like Methicillin-resistant Staphylococcus Aureus or MRSA.
Turf abrasions, often referred to as turf burns, are more frequent and severe on artificial turf compared to natural grass, creating openings for MRSA to enter. The infection can spread through skin-to-skin contact, leading to MRSA outbreaks. A 2005 study published in the New England Journal of Medicine found that these abrasions occur more often and intensely on artificial turf during games and practices. The combination of frequent abrasions, often left uncovered, and the prevalent skin-to-skin contact in sports like football contributes to the serious health risks associated with artificial turf abrasions.
An article published in the Philadelphia Inquirer in March 2023 has amplified concerns regarding the potential health implications of artificial turf, particularly its potential connection to a rare brain cancer. The article shed light on the deaths of six professional US baseball players, all of whom succumbed to glioblastoma, a severe form of brain cancer. All six athletes had spent substantial periods of their careers with the Philadelphia Phillies that played on an artificial turf field between 1971 and 2003.
The Philadelphia Inquirer article focused on the presence of per- and polyfluoroalkyl substances (PFAS) within artificial turf, which is being investigated as a possible catalyst for cancer. The article underscores that testing performed on samples taken from the former turf field used by the Phillies revealed the presence of 16 distinct varieties of PFAs within the turf.
Numbering roughly 12,000, per- and polyfluoroalkyl substances (PFAs) are man-made chemicals known for their water- and grease-resistant properties, and used in various consumer products like cookware, clothing, and cleaning items. They are called “forever chemicals’ because they don’t break down naturally.
PFAs can be ingested, inhaled and absorbed through the skin – or even enter the body through scrapes and other wounds. They are linked to developmental issues, liver and kidney damage, immune system disruptions, and cancer risks because they tend to accumulate in organisms.
Research has discovered traces of PFAs in the blades and backing of artificial turf. The research however suggested that PFAs are used as an extrusion aid in turf grass blades to prevent polymers from sticking to the extruder rather than being actual ingredients in artificial turf.
Tire debris, known as crumb rubber, is commonly used as infill material in artificial turf fields. This recycled material is processed into granules and spread across the turf to provide cushioning and support. Depending on its size, a single artificial turf field requires between 20,000 to 40,000 shredded tires for its coverage.
EPA testing has detected elevated levels of hazardous chemicals in crumb rubber, giving rise to worries about players being exposed to substances such as heavy metals, benzene, volatile organic compounds, and other carcinogens.
The health risks associated with exposure to crumb rubber are multiple and concerning. For instance, contact with tire rubber used as infill can lead to allergic or toxic dermatitis. Furthermore, the inhalation of tire rubber components or particles can irritate the respiratory system, potentially exacerbating asthma symptoms. As synthetic fields degrade over time, the materials used break down into smaller pieces, including tiny microfibers. These particles can be easily inhaled, particularly when players fall or slide across the synthetic surface. Needless to say, athletes, who frequently come into contact with and inhale these materials, are particularly at risk of health impacts associated with crumb rubber infill.
Interestingly, the recognition of these dangers has led to regulations prohibiting tire disposal in landfills or oceans. This situation underscores the irony that significant quantities of this potentially unsafe material exist in environments where children and professional athletes have direct contact with recycled tires.
In a 2017 article titled Artificial Turf and Cancer Risk published in the Journal of the National Cancer Institute, author Daniel Luzer delved into the growing concerns surrounding artificial turf and its potential links with cancer. Luzer wrote how Amy Griffin, the associate head coach of women's soccer at the University of Washington, had initiated inquiries into the purported link between artificial turf and cancer in 2009 after she found two former goalkeepers who had spent their formative years playing on artificial turf had been diagnosed with lymphoma.
Luzer's article had underscored the presence of crumb rubber, colloquially known as the ‘black dots’, utilized as infill on artificial turf fields. Composing ground rubber from used tires mixed with sand, these rubber granules contain elements like mercury, benzene, and arsenic, evoking concerns about potential carcinogenic properties. While there was no conclusive evidence of a direct connection between crumb rubber turf and cancer, Luzer's article emphasized apprehensions over the bio accessibility of contaminants and the proximity of soccer players, particularly goalkeepers, to the turf.
Here's an excerpt from the article:
“The black dots contain mercury, benzene, and arsenic. [Amy] Griffin discovered that although scientists don’t know that crumb rubber turf causes cancer, they also don’t know that it’s safe.
“‘I’ve been at the University of Washington for 21 years,’ Griffin said. ‘And for 15 years I saw nothing. I knew no one with lymphoma. But now, personally, I know six people who’ve had cancer.’ By 2010 she had heard of 12 soccer players with cancer and decided to keep a list. She now has a list of 230 soccer players, nearly all goalkeepers, who have played on artificial turf and developed cancers. ‘Why is this?’ she said. ‘I thought it might be like asbestos, where it took 35 years for people to see the danger.’”
But is there any scientific evidence of health risks associated with crumb rubber and whether crumb rubber spread in sports fields had compounds present in quantities that would pose a health risk to humans?
A study titled Impact of tire debris on in vitro and in vivo systems' published in the journal Particle and Fibre Toxicology, tested tire debris generated from road tire abrasion on frog embryos and human cells. The study revealed that higher concentrations of this debris were associated with increased toxicity.
Using a solution of tire debris that was not diluted much caused a significant number of frog embryos to die, and this effect was even stronger than a solution that was twice as concentrated. When human liver cells were exposed to tired debris, they started accumulating zinc after just four hours of exposure. Another type of human lung cells, when exposed to a part of tired debris, showed changes in their appearance, stopped growing properly, and had more damage to their DNA after being tested for three days. Using a moderate amount of tire debris on frog embryos caused some of them to die or develop abnormally. These results suggest that tire debris can be harmful to both frog embryos and human cells.
With regard to whether crumb rubber had compounds present in quantities that would pose a health risk to humans, a 2022 study analyzed 42 organic compounds in 91 synthetic turf football pitches from 17 countries. It found hazardous compounds (PAHs, plasticizers and vulcanizers) in all samples. Some samples exceeded the recently established 8 ECHA PAH limit (20 μg g−1) but most crumb rubber samples exceeded limits for intensive contact.
A news report quoted one of the researchers, Jacob de Boer, a Professor of Environmental Chemistry and Toxicology at the Free University of Amsterdam, as saying: “We are very worried about it… There are also these P-FAS compounds which have an effect on your immune system, and that effect is much more sensitive than for cancer.”
The report added that he clarified that the risk was likely related to how long and how closely players are in contact with the turf. “It’s not a matter of one game or one day or a week, but if you do it regularly, training for years, and you play all your matches there, then it is a problem, so the dose is important,” it quoted de Boer as saying.
This buttresses Griffin’s argument that athletes who are exposed to crumb rubber more intensely (like goalkeepers who drop to the ground again and again) and over a longer period of time are more likely to suffer associated health risks such as cancer.
In recent years, legal actions taken by players related to concussions while playing underscore the seriousness of the current concerns raised about artificial turf surfaces. Notable cases include an August 2019 settlement that mandated the NCAA to allocate $70 million for concussion screening and testing for former college athletes. Furthermore, an additional $5 million was allocated towards medical research in this area. The NFL also faced its own reckoning, with a landmark $765 million settlement reached in October 2021. This settlement addressed the issue of concussion-related brain injuries among its retired players, encompassing approximately 18,000 individuals.
An Attorney Analysis published in July 2023 in Reuters titled, Turf wars: The courtroom battle over artificial turf safety may be closer than we think, said: “Given recent publicity and the NFLPA's involvement in the issue, lawsuits claiming personal injury resulting from play on turf may be just around the corner. This could generate a mass of prospective plaintiff athletes just as we saw with the concussion litigation of years past.”
While the health concerns associated with artificial turf raise significant questions, it's equally crucial to explore the impact of artificial turf and its components on the environment.
After the 8–12-year warranty of an artificial turf field expires, its disposal becomes a concern. Many of these fields end up in landfills, releasing plastic and rubber into the environment, contaminating water sources and ecosystems. Crumb rubber also poses a microplastics threat as it breaks down, releasing particles that harm soil and aquatic systems, affecting plant growth and aquatic life.
The New York Times-owned product review website, the Wirecutter, highlighted the environmental pollution caused by artificial turf in an article titled Why we don’t recommend artificial grass for most people. It said while the exact amount of microplastics entering waterways via synthetic pitches' runoff remains challenging to determine, conservative estimates suggest hundreds of kilograms per pitch per year. It highlighted the findings of academic research from Sweden, Denmark, and the UK to buttress its point. It said in Sweden, these fields are even considered the second-highest contributor of microplastics to waterways. Researchers discovered microplastics in 85% of soil samples collected near artificial grass pitches in Norway. The Wirecutter said although research on this topic is limited in the US, the cumulative impact of runoff from the 265 million square feet of installed synthetic grass is a concern that demands attention.
A few of the biggest arguments in favor of artificial turf is that:
1. It is easy to lay and maintain.
2. Using artificial turf helps conserve billions of gallons of water each year and eliminates the need for pesticides, fertilizers and mowing to maintain grass fields.
3. It creates places for recreation and leisure that helps children, adults and athletes to exercise all year round, and the benefits of exercise potentially outweigh the risks of artificial turf and crumb rubber.
But what if we tell you that in recent years, technology and innovation have introduced a game-changing solution? Capillary Hydroponics, a groundbreaking technology, offers a sustainable alternative that allows you to grow natural grass with all the conveniences of artificial turf. This revolutionary system not only ensures year-round usability and easy maintenance of sports fields and arenas but also minimizes water consumption, eliminates the need for harmful chemicals, and promotes healthier growth with its advanced irrigation approach.
But first let’s address the myth (yes myth) that synthetic fields require less maintenance than natural turfgrass fields or that they are maintenance free.
Synthetic/ artificial turf fields require the following:
Additionally, artificial fields need replacing every 8-10 years, whereas a natural turf field does not need as frequent renovation and can be renovated at a much reduced price compared to an artificial field.
Then, there is the hidden cost of disposal. Because the field is filled and top-dressed with a crumb rubber, the material may require special disposal. In 2009, one estimate put the disposal costs at $130,000 plus transportation and landfill charges.
In 2005, turfgrass specialist Brad Fresenburg came up with an annual average cost for each field type in a 16-year scenario as follows: the natural soil-based field, $33,522; the sand-cap grass field, $49,318; the basic synthetic field, $65,846; and the premium synthetic field, $109,013. (See here).
“CapillaryFlow and its founder Martin Sternberg, CGCS, has invented the first ever hydroponic system to grow turfgrass, and it will change the way we build and manage turf in the future.” These are the words of Dr Thom Nikolai, one of the world’s leading scientists in turfgrass.
Capillary Hydroponics is a radical new irrigation system that uses an oxygenated and fertilized moving underground water table to grow turfgrass. In doing so, it decreases water loss and consumption by up to 85% while ensuring that the turfgrass grown is stronger and more durable with significantly less maintenance and environmental impact.
Dr Nikolai is spearheading a study that is comparing Capillary Hydroponics to Variable-Depth Rootzones, the latest in USGA technology, at Michigan State University’s Hancock Turfgrass Research Center. The research, which started in June 2022, is comparing the two systems for economic and environmental impacts, but the focus in the first two years is water consumption.
At the core of Capillary Hydroponics is Capillary Material, formerly known as Capillary Concrete. This patented and engineered polymer-based pervious concrete is the only building material that can rapidly drain water while also moving water up. Invented in 2009, it is also behind one of CapillaryFlow’s most successful solutions, Capillary Bunkers, which has transformed the way the golf industry constructs and maintains bunkers.
The Capillary Hydroponics system comprises several layers: an impermeable liner that sits on the soil, drainage pipes, drainage gravel, a layer of Capillary Material, washed sand and finally grass. The area under the surface is split into two equally large parts. A control basin filled with water is placed on the outside and has pipes that feed into the middle of each cavity. It automatically oxygenates and pumps fertilized water back and forth between the two sections several times a day, watering the roots as it goes. When the water moves and enters or exits the pores of the root-zone material, the gas exchange increases by up to 6,000%.
The level of the water table is completely controllable and the water moves between each cavity at a fully adjustable rate too. This system minimizes the amount of water required and promotes strong root growth.
Capillary Material ensures a perfectly flat and level base beneath the rootzone, which is crucial for the functioning of a hydroponic system.
The benefits of using the Capillary Hydroponics system to grow grass in sports fields are many:
To conclude, the history of the tobacco and asbestos industries serves as a stark reminder that it can take decades to establish the true risks of a product, even in the face of compelling scientific findings.
Take the tobacco industry. The link between smoking and cancer began to emerge in the 1920s and became progressively clearer with studies in epidemiology, animal experiments, cellular pathology, and chemical analytics. By the 1950s, research indicated a causal connection between smoking and cancer, leading to the US Surgeon General's landmark report in 1964 that marked a turning point in the recognition of the harmful health effects of cigarette smoking. Yet, the tobacco industry maintained its stance, disputing the evidence and promoting the perception of a scientific controversy. In fact, as recently as 1994, top executives of major US tobacco companies provided testimony to Congress claiming that the health risks of smoking were inconclusive and denied targeting children in their marketing efforts. However, within weeks of this testimony, documentary evidence emerged that exposed that the tobacco industry had known for decades that cigarettes cause early death, that tobacco was addictive and that their initiatives regarding support for smoking and health research were an eyewash.
In the case of asbestos, evidence indicating its dangers emerged as early as the 1910s, with insurance companies refusing to cover asbestos workers due to emerging cases of asbestos-related illnesses. Nevertheless, the industry downplayed the risks, resulting in decades of global occupational cancer cases. It took until the mid-1970s for Sweden to enact a partial ban on asbestos. Switzerland and many other European countries followed suit 15 to 20 years later, and the European Union banned asbestos in 2005. Today, however, just a quarter of the World Health Organisation’s member states have banned asbestos.
Parallels can be drawn between the tobacco and asbestos industry’s tactics and the current discourse surrounding artificial turf. The question is: Do we really need to wait for irrefutable proof that artificial turf is a health and safety risk for children, adults and the environment?
The examples of tobacco and asbestos should remind us that the path to confirming and addressing the dangers of a product can be lengthy and challenging. When considering the health and safety implications of artificial turf, it's crucial to heed the lessons of the past.