Commentary: Best available science indicates no reason for turf health concerns

The Edmonds City Council’s decision to impose an 18-month freeze on the installation of turf fields with crumb rubber infill appears to rest on the assumption that there is substantial uncertainty regarding chemical exposures from this product. There is always at least some uncertainty in all areas of scientific inquiry, but the key is to look to the best available science. In the case of synthetic turf, the best available science indicates that there is no reason for concern about health risks for users of these fields. Dozens of peer-reviewed journal articles and multiple state health agencies support this conclusion, and some have reviewed the evidence as recently as this year.

It is certainly understandable that parents and community members want to be prudent and take every possible precaution in protecting their children. But the discussion of potential health risks needs to be informed by the science, and also provided with context. For instance, studies that have examined chemicals in synthetic turf have found concentrations for some are similar to, or lower than, those found in natural soils. In addition, the finding of chemicals in a substance does not necessarily imply a health risk. We interact with products with potentially harmful chemicals and carcinogens every day (e.g., your iPhone, your computer, your carpet). However, because exposures are low there are generally not concerns for health effects.

Children’s safety—both now and in the long-term—is absolutely paramount. But fear devoid of evidence shouldn’t undermine the science. In the case of synthetic turf, the best available science indicates no health concerns for people using these fields. Hopefully, over the course of the next 18 months, Edmunds officials and residents will analyze the available data and come to the same conclusion.

— By Michael Peterson

Michael Peterson is a board-certified toxicologist at Gradient, an environmental and risk sciences consulting firm. He serves as scientific adviser to the Recycled Rubber Council.

  1. Sometimes, Michael, the “evidence” isn’t available until time passes. Who’s to say the “best AVAILABLE science” today won’t change tomorrow as we discover new things about this crumb rubber? I hear no mention of that in your commentary.

    1. First, a huge heart-felt thank you to our Edmonds City Council for unanimously voting to ban crumb rubber in Edmonds for at least 18 months. They did their research, they listened to their citizens, and they prudently decided to follow the precautionary principle to protect our children, citizens, and environment until real, substantial research can be done. Research that takes into account the ways the carcinogens, heavy metals, and carbon black contained in the crumb rubber infill can be transferred to humans, animals and plants…in the doses that are actually being delivered, at the temperatures they are delivered, for the length of time of delivery, in the combinations delivered. Those are very very different concerns from most “available science” to date. In fact, there have been NO long term studies to track the effects of the above mentioned issues. The only such studies that are currently underway are the unofficial ones using our children, citizens, and environment as the subjects.

      How many years were cigarettes considered harmless? They were even kindly included in the rations given to GIs! How long was asbestos considered not only harmless but just plain wonderful; something to be included in hundreds of products where you wouldn’t even suspect it, even while asbestos companies were socking money away for the lawsuits that would eventually come.

      But time passes, and we learn. We remove lead from gasoline. Asbestos abatement companies spring up, and school districts are careful to use them when they remove asbestos. The various governmental agencies who were so enthusiastic about crumb rubber infill as a way to get rid of used tires are now backing away from their recommendations. Congress has expressed concern and has asked the EPA some serious questions, and the EPA, who backed away from their original stance, wants more studies done, but the funding isn’t there.

      We do indeed interact with things like smartphones regularly. Usually we don’t heat them up to the temperatures found on crumb rubber infilled fields, and usually we don’t grind them up into tiny bits, rub them into our cuts, breathe them, nor swallow them. Daily. For years. We also don’t make our fish swim in their run-off. Come on Mr. Peterson…to put cellphones and crumb rubber infill in the same category is not only ridiculous, It makes me think you believe Edmonds residents are stupid!

    2. Gradient, a non-biased info source? I think not.

      • “Gradient’s game, says Richard Clapp, professor of environmental health at Boston University’s School of Public Health, “is product defense. Its services include promoting industry positions in op-eds, providing expert testimony in court, legislative, and regulatory proceedings, and issuing scientific reports…. They wind up defending people who are worried about liability,” Clapp says, “though they would say they’re there to make sure that there’s sound science behind whatever regulatory steps or litigation happens in this country.” (13)]
      • “This is a company that basically works for industry, and their job is to trash environmental studies,” said Joel Schwartz, a professor of environmental epidemiology at Harvard and director of the university’s Center for Risk Analysis.

  2. “Fear devoid of evidence”…that pretty much says it all about the anti turf campaign, doesn’t it? A question that comes to mind: how many of the anti turf group actually have kids that play organised sports? Or are they really environmentalist fringe masquerading as concerned standard bearers for child safety? And isn’t it very “NPR-esque” to find a frustrated academic who will support an extreme environmental position without evidence. The Edmonds City Council is pathetic for bowing to a vocal minority while the true majority spends their time with actual life priorities other than council meeting drama, and thank the Lord for a school district superintendent with guts.

    1. Michael,
      Not that it really matters who is putting in the effort and speaking up to protect human and environmental health, but to answer your question- the majority of those involved locally and across the nation are parents with children who play sports, and we want the safest fields for our children. This includes the avoidance of unnecessary exposure to carcinogens AND superior concussion and injury protection.

      The cushioning protection provided by crumb rubber can also be provided with a non-toxic infill and superior padding system under the turf carpet (which will also cut down on lower extremity stress and injury), or with well built sand capped grass fields and maintained with organic methods. Either of these will provide superior concussion prevention while cutting down on the heat, lower extremity injury, and exposure to the KNOWN carcinogens that all come with the use of crumb rubber. We have other choices!

      There are many options….crumb rubber is only one of them. While less expensive upfront (because it is a cheap waste product), there are additional costs to dispose of the tire mix at end of useful life (8-10 years)….not to mention the human and environmental cost.

      As for evidence…. there is plenty to make you go hmmmm. Why take the risk, especially one where we know the ingredients which have been shown to cause harm to human health are present. We are making decisions that will impact our children’s future health.

      Visit for more info.

  3. In response to Michael Bury, I want to ask if he thinks only people with young children should care about young children? That is such a terribly egocentric position to take. What keeps communities strong is citizens who care about others, regardless of whether the “others” are their own or not.

    In response to Cam Peterson, “THANK YOU” for providing some highly credible sources that are knowledgeable about Gradient. Some people are willing to defend a corporate interest regardless of the potential harm to humans, other animals, or the environment. I sincerely and earnestly hope that everyone who reads your post or hears your evidence about Gradient will pay attention and realize that there is a huge conflict of interest in this situation.

  4. I, for one, am proud to live in a city where law-makers take seriously the health, safety, and environmental concerns of citizens. Over 1,000+ Edmonds residents signed a petition asking for the City Council to ban crumb rubber infill (MUCH different than artificial turf, by the way), and citizens in communities across the nation are doing the same. Kudos to the council for be willing to take a lead on this. The history of how ground up tires ended up on athletic fields used by children is fascinating and worth taking time to learn– and the resistance to its use is not limited to a “small, but vocal minority”, but is a national movement full of parents, citizens, and in some cases, whistleblowers.

    Until there is ONE long-term study done, why in the world take a chance with the health of our children? There are natural infill options used widely in Europe, and which are readily available here in the US/Washington State– it is not a choice between crumb-rubber infill or nothing, we do have options.

    Neither the EPA, nor the Consumer Product Safety Council are willing to say crumb rubber infill is safe. Why not err on the side of caution and use an alternative?

    And, by the way, also fascinating and worth a read– the actual content of those “dozens of peer-reviewed journal articles”. When experts throw around statements about scientific research, it is the responsibility of citizens to read the fine print. The more citizens know, the more power we have.

  5. If the  “best available science” on crumb rubber contains data gaps and lacks long term health studies- as recently noted by both the CPSC and EPA- then our children deserve precaution and common sense! 

    Edmonds City Council members looked at the evidence (or lack of) considered the potential for risk, and voted UNANIMOUSLY to take precautionary measures to protect the public.

    Crumb rubber contains a multitude of toxins and carcinogens. There are MSDS warnings for tire recycling industry workers advising of precautions. As a recycled product it is unregulated, so there is no agency providing safety oversight. Additionally, there are safer alternatives to the CHOICE to use crumb rubber. It is only one component of artificial turf.

    Who do you want to trust first for advice on your child’s health and safety? Someone paid to defend product safety or someone concerned with children’s health?

    Michael Peterson is a toxicologist with Gradient Corp. As noted, he serves on the Recycled Rubber Council- which has an interest in the continued use of crumb rubber. Gradient has also defended the tobacco industry, BPA, and arsenic in playgrounds!  They are regulatory toxicologists hired by industry to show product safety. They are NOT health effects researchers focused only on human and environmental health. Read this article for more info on regulatory toxicologists vs health effects researchers.

    Recent statements concerning crumb rubber from Government and Health Effects Professionals:

    Environmental Protection Agency (EPA) Spokesperson Liz Purchia called existing studies inadequate, and said “new science” is needed to answer questions about turf safety and that “existing studies do not comprehensively address the recently raised concerns about children’s health risks from exposures to tire crumb.”

    Consumer Products Safety Commission (CPSC) Chairman Elliot Kay stated “safe to play on means something to parents that I do not think we intended to convey and I do not think we should have conveyed.”

    Jeff Ruch, Attorney with Public Employees for Environmental Responsibility (PEER) “We (in the U.S.), for the most part, operate under the principle that your chemical is innocent until proven guilty. It goes into a stream of commerce and only if it produces a body count is there then any regulatory response.”

    David R. Brown: ScD (Doctor of Science) Public Health Toxicologist Director of Public Health Toxicology for Environment and Human Health, Inc.; Past Chief of Environmental Epidemiology and Occupational Health at Connecticut’s Department of Health; Past Deputy Director of The Public Health Practice Group of Agency for Toxic Substances and Disease Registry (ATSDR) at the National Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia: When he was asked what advice he would give parents thinking of letting their children play on turf fields: Brown was adamant “My basic advice is, don’t do it,” he replied. And what if there are no other alternatives to artificial turf fields? “If we feel the need to use [turf fields], I’d require that everyone shower and that they use only shoes that they would use on that field and that they not wear the same clothes in and around afterwards, because you want to reduce the chance that [tire crumbs] would be ingested.” In the absence of conclusive long-term studies on the known carcinogens found in some artificial turf fields, Brown believes it’s better to be safe than sorry.
    Dr. Brown was asked when he thought that people would start to take notice of the cancer-related harms of artificial fields. Ten years? Fifteen?  “Five,” he said. “Five years. Because we’re putting first graders and cancerous materials together. ”He continued: “And when the cancer starts, people like myself will be sorry we didn’t argue more effectively.”
    D. Barry Boyd, MD: Clinical Professor of Medicine, Yale University School of Medicine, Oncologist at Greenwich Hospital and Affiliate Member of the Yale Cancer Center warned that “because artificial turf playing fields are disproportionately used by children and adolescents, these childhood exposures to environmental carcinogens may add to lifelong risk of cancer.”

    Philip J. Landrigan, M.D., M.Sc., is a pediatrician and epidemiologist. He has been a member of the faculty of Mount Sinai School of Medicine since 1985 and served as Chair of the Department of Preventive Medicine since from 1995 to 2015. He was named Dean for Global Health in 2010. He served for 15 years as an Epidemic Intelligence Service Officer and medical epidemiologist at the Centers for Disease Control and Prevention (CDC) and the National Institute for Occupational Safety and Health (NIOSH): Dr. Landrigan submitted a letter to the New York City Planning Department last year expressing concerns over the carcinogens in tire crumbs. He wrote that the principal chemical components of crumb rubber are Styrene and Butadiene — Styrene is neurotoxic, and Butadiene is a proven human carcinogen that has been shown to cause leukemia and lymphoma.  “There is a potential for all of these toxins to be inhaled, absorbed through the skin and even swallowed by children who play on synthetic turf fields,” Dr. Landrigan wrote. “Only a few studies have been done to evaluate this type of exposure risk.”

    “Children go to playgrounds almost daily,” said Dr. Landrigan, dean of global health at New York’s Mt. Sinai Hospital and a top expert on the effect of chemicals on children. “And gifted athletes are on the soccer filed almost every day. That sort of cumulative exposure results in a buildup in their body of these toxic chemicals, and can result in a buildup of cellular damage that’s caused by these chemicals, that can then result in disease years or decades later.”  “Little children should not be put in a situation where they’re forced to be in intimate contact with carcinogenic chemicals,” Dr. Landrigan added. 

  6. Thank you again, Laura for all your work and research and for speaking up loud and clear regarding this huge profit making questionable product. Thank you to the citizens that spoke up, Senator Chase, the scientists and our Edmonds City Council for making the right decision regarding this product.

    With current science and KNOWING what we now know regarding the state of our environment, human health safety concerns, animal health safety, extinction of species due to human activity, man/woman made pollution in our environment, I applaud all that have recognized this is a major concern.

    I am sorry to see that there are so many people that will lobby for industries that appear to me to put money and profits above all else including the health of our children.

    I believe the time frame regarding poisonous, harmfull and deadly asbestos use for profits for many large companies was 1938 to around 1981 when its use was FINALLY fully stopped. A lot of people have died and continue to die with mesothelioma…….all for the sake of huge money profits for an industry that knew of the dangers at the get go……..and asbestos s still floating around!!!

    Common sense and science tells us everything………common sense

  7. There is ABSOLUTELY no uncertainty regarding the chemical contained within tires or the recycled crumb rubber mix. Tires contain many known toxins and carcinogens, an undisputed fact.

    The uncertainty hinges on the “bio-availability” of the harmful chemicals. Synthetic turf and recycled rubber industries claims that although the recycled mix does contain a multitude of heavy toxins and carcinogens, they are “locked” inside the rubber crumb matrix, and therefore not bio-available to humans.

    The following Washington State University Extension study on landscape rubber mulch that proves that is NOT the case and begs the need for precaution while real life/long term testing is conducted to determine the potential for harm to human health from repeated exposure to crumb rubber.

    Rubber Mulch Fact Sheet- from Washington State University Extension- is documentation that ground-up rubber tire mulch will kill living plant life and many aquatic organisms. Studies on the short life-cycle of plants and small aquatic organisms yield results in a fraction of the time and are more feasible than human studies. The study shows that toxic chemicals DO IN FACT each out of the larger rubber mulch used for landscaping and are therefor bio-available and causing harm to organisms.

    Both products are made from recycled tires, therefore the same chemicals will also leach out from crumb rubber; especially since the smaller the particle size of crumb rubber, means larger surface areas, greater breakdown, and a greater the potential for leaching. This means the chemicals and heavy metals leach out of the small crumb rubber in synthetic turf fields at a greater rate even than the rubber mulch. Field users are exposed to these chemicals through dermal contact, inhalation, and ingestion. Without long term human health studies which study all modes of exposure, we do not have the information required to determine safety.

    From the publication: “Decades of research have confirmed that entire aquatic communities of algae, zooplankton, snails, and fish can be killed when exposed to rubber leachates.”

    “The leaching problem increases as the particle size of recycled tires decreases. In other words, the smaller the particle size, the greater the potential for leaching. Toxins associated with crumb rubber, a more finely ground type of rubber used on athletic fields, are well documented. Benzothiazole, a toxic, airborne contaminant from crumb rubber, is the primary rubber-related chemical found in synthetic turf studies.”

    “Polycyclic aromatic hydrocarbons (PAH) such as naphthalene, phthalates, butylated hydroxytoluene, and otherchemicals of concern have been found in the air, water, and soil adjacent to crumb rubber and other recycled tire products.”

    “Research provides additional evidence regarding the potential health risks associated with exposure to crumb rubber in turf fields and playgrounds.”

  8. Shame on those that refer to “environmental fringe”(that rhetoric goes way back to before environmental science and lobbying in my book……..)

    .One need only live here in Edmonds, up close and absolutely tied into mother nature because of our fortunate geography here……up close and personal, the sea, the living sea life, the wildlife, birds, all living beings that share this small space…..the sky and the very air we all living beings need to breathe …….to know whats important……the very air we need breathe

  9. Recently I was on the ground, up close and personal, at Woodway field and reached through the fence (the irony of the big white sign of all the things not allowed at or on the field) and had a small amount of the crumb rubber in my hand……..I would not even call it particles… felt like dust in my hand. ….” the smaller the particle size the greater potencial for leaching”……..

    In my opinion, this product will be easily be blown or distributed throughout our environment, if not already, very quickly. Besides the immediate safety for ALL living things, I see very big consequnces down the road…..

    How anybody came to the conclusion this is ok and fine (when there are safer altrnatives in the industry) is simply astounding to me. Saving money at the expense of children, if this be the case, is even more astounding and I say, who EXACTLY put this together?

  10. I have to suspect (since more money was offered by Verdant for a different infill for the synthetic turf fields) that the school district’s insistence on using crumb rubber infill on the old Woodway field and others, has more to do with some sort of back-door agreement than saving up-front money Other infills are available. About 1000 citizens signed petitions against crumb rubber within a short period of time without the benefit of professional petition signature gatherers, yet the district didn’t care.

    Thank you Rebecca Wolfe, for pointing out what should be obvious; we should ALL care about each others welfare, and that of the environment in which we all live!
    And thank you Tere Ryder for your comments, I totally agree. Also a continuing thank you to Laura Johnson for her advocacy, research, and documentation. You provide the opportunity to learn for so many of us.

    And I have to say, I take umbrage at the notion that those who take time out of their personal lives to follow what is going on in our city, to research issues, and to provide information to policy makers, are are somehow “less than.” Those others, who are too busy to care, are thus uninformed, and are willing to have their personal health and fate determined by those who may very well NOT have the best interests of the citizens and environment at heart.

    Casting stones, or putting your head in the sand doesn’t make the problem go away.

  11. I would also be interested to know when Mr. Peterson came to believe he was an expert on crumb rubber. When he presented his report to the Verdant Health Commission, he was unable to answer several very basic questions about crumb rubber that council members asked. The answers to these questions can be found in the most well-known studies on crumb rubber, studies he had apparently not read.

    The study he did for Verdant was nothing more than a comparison of industry-supplied data on the levels heavy metals and other toxic chemicals in samples of their products to the US EPA Residential soil guidelines for these chemicals. Levels of heavy metals in soil in Western Washington were also noted. When levels of toxic chemicals in the crumb rubber were in excess of the allowable levels in soil, Peterson concluded they still did not pose a human health treat. He regarded the EPA screening levels as excessively cautionary. Data from third party studies, such as studies sponsored by state governments were relegated to the appendix and was not analyzed.

    I have found that when people start insisting that decisions about using crumb rubber be “scientifically informed” or be based on the “best available science” they either don’t understand all of the science involved or they have some other reason for wanting crumb rubber to be used. The reality is that crumb rubber exposes people to numerous known toxic chemicals. We can’t reliably the estimate risk these chemicals pose because no study has comprehensively measured exposures under real world conditions. We also don’t have any toxicity data on approximately half of the chemicals in crumb rubber, so the list of toxic chemicals may be incomplete. Finally, we have no way of estimating the cumulative effect of the simultaneous exposure to all of the toxic chemicals in crumb rubber. Often, chemicals act synergistically so that the net effect is greater than the sum of the parts. We can’t reliably estimate risk using models right now. There have been no studies of the effects of crumb rubber on animals, and no comprehensive epidemiological studies on humans are underway. Science can’t tell us what the risk is right now.

    In the face of scientific uncertainty, we are left to make a decision based on values. Do we choose alternative infills or alternative field types to protect the health of our citizens and our environment? Or do we continue to use crumb rubber to protect industry? What is our first priority, human health or corporate profits?

    The Edmonds City Council listened to testimony and a public presentations by two toxicologists. They listened to testimony from other Ph.D. level scientists, and other health care professionals. They also listened to the citizens, including athletes and parents of athletes. The Council made a courageous, rational, decision informed by science and based on the values of the community. Any implication that the Edmonds City Council made an decision based on uninformed fear is insulting not only to the council but also to the community as a whole. Mr. Peterson, you owe the Edmonds City Council as well as the City of Edmonds an apology.
    Christi Davis, Ph.D.
    Resident of Brier

  12. In response to Michael Bury.. I find it offensive that you think anybody who is opposed to crumb rubber, and does not have children, are merely “environmentalist fringe masquerading as concerned standard bearers for child safety”. How in the heck do you know what we are concerned about? How dare you make such assumptions. All citizens should care about the health, welfare & safety of the children in our neighborhoods regardless of whether they are our offspring or not. And to further say that we are “supporting an issue without evidence” oh to the contrary. There is enough long-term evidence on numerous other things that have been proven to be hazardous to our health that were deemed “safe” back in the day (cigarettes, asbestos, etc). It doesn’t take a genius to realize we should err on the side of caution with children’s lives and health. If you can’t understand or grasp that then I feel sorry for you and your children if you have any and especially if they play sports on those fields with crumb rubber.

  13. I was watching last nights bowl game on my new 62 inch TV. Any time there was a disputed call a touchdown, hard hit or injury the camera would give us a close up as it zoomed right in on the site..
    One announcer says to the other, what is that stuff that bounces up off the turf when these players hit the ground?
    Oh, that’s the crumb rubber answers the other announcer.
    Cigarettes,alcohol and drugs are a choice that we all get to make. It is then our decision if we choose to over do it on the way to harming ourselves. Not so with crumb rubber. We don’t know how long it will take before it starts harming our children or grandchildren. I want those people who are holding on to this time bomb to get over their need to be right. I came late to the game so I researched it on my own. here is what I know. Some people are willing to expose our youth to the potential risk of crumb rubber. I will not.Their is a shrinking crowd of people left holding the bag filled with crumb rubber. Most of us didn’t know it at the time but this game was rigged from the start.

  14. Sometimes all that’s necessary is a little logic . . .

    re: “the best available science”
    any chance that might be tempered if you’re livelihood depended on your findings???

    Mr Peterson’s livelihood is through “Gradient, an environmental and risk sciences consulting firm”,

    on their web page: Industries served: Chemical & Pharmaceuticals

    ’nuff said/written?

  15. Wow…THAT got you fired up, huh? I’m headed out to play soccer with the kids – you should all try that some time. Merry Christmas!

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