Are Foam Blocks Dangerous To Gymnasts? By Drs. Bill Sands and Courtney Carignan

Update July 2016: Dr. Carignan has released a follow up study that can be found here. This confirms the initial thoughts found here in this post. 

An Open Letter to Gymnastics by Dr. SandsAn Open Letter to Gymnastics by Dr. Bill Sands

Dr. Bill Sands has submitted this article for Gymnast Care to publish and he has written an open letter to the gymnastics community. Please read the letter first by clicking on the picture of the letter or the pdf by clicking the below link.

See Dr. Sands Open Letter to Gymnastics by clicking here (pdf). 

The article below is a great article and deserves much consideration. Consider sending a sample of your foam in…see the last paragraph for more details.

Thanks for joining us for another Gymnast Care special on protecting gymnast’s health.

Flame Retardants and Gymnastics Foam

Written by William Sands, PhD, of the FIG Scientific Commission and Courtney Carignan, PhD, Harvard University.

Edited and endorsed by all members of the FIG Scientific Commission

A recent study on the presence of flame retardant chemicals in gymnasts’ blood showed relatively high levels of a brominated flame retardant chemical mixture, PentaBDE, believed to be due to the use of flame retardants in the foam of landing mats and jump pits [1]. Flame retardants, such as PentaBDE are added to polyurethane foam and many other products during the manufacturing process. Foam products treated with flame retardants have been used for decades in hundreds of applications, from furniture cushions to pillows to car seats, with the intention of improving fire safety.

Over the past decade the addition of flame retardants has become controversial when it was discovered these chemicals readily escape these products, enter the air and dust and deposit in our bodies where they can remain for years [2]. One important way that flame retardants enter the body is by accidentally ingesting dust that is on the hands. People who wash their hands more frequently generally have lower levels of flame retardants in their bodies [3]. Flame retardants can also be inhaled and absorb through the skin [4,5].

What’s Causing The Issues?

PentaBDE was the flame retardant mixture most widely used in polyurethane foam in the U.S. People in the U.S. have higher levels in their bodies, on average, than any other country in the world [6]. It takes years for the levels of PentaBDE in the body to be reduced by half [7] and is now known to be an endocrine disrupting chemical, which means it can alter levels of thyroid hormone in the body. Scientific study is ongoing; to date it has been implicated in a number health concerns including reduced fertility [8]and increased incidence of ADHD among children whose mothers had higher levels in their bodies [9].

Is It Already In Their Blood?

A year ago a group of researchers from Boston University, Duke University and the Centers for Disease Control published a study investigating flame retardants that included eleven female volunteers from a U.S. collegiate gymnastics team [1]. Each volunteer donated a sample of blood and provided wipes from their hands. Samples from the air, dust, and foam were obtained from their gym. BDE-153, a component of the PentaBDE mixture, was present in the gymnast’s blood at levels up to 6.5 times higher on average than the general U.S. population. Higher levels of PentaBDE and other flame retardants were found on hand wipes collected after practice compared to before, in the gym’s pit cubes and at elevated levels in the gym air and dust. Bromine, as a marker of brominated flame retardant, was identified in the foam of many of the 10 and 20 cm (4” and 8”) landing mats, ‘sting’ mats, and in the carpeted portion of the vault runway.

Is Foam Important?

Gymnastics is dependent on soft cushioning products and technologies to absorb the forces of landing impacts. Historically, grass, sand, water, springs, horsehair, suspension ropes, trampoline beds, and nets, among others have served as protective landing surfaces and devices [10]. The invention of foam products of varying materials and designs has served the cushioning and safety needs of gymnasts and many other athletes (e.g. loose foam pits used by ski jumpers, snowboarders and trampoline gyms, track and field landing pits [11], boxing and striking pads [12], and various mat and padding devices [13]). Manufacturing methods may vary. For example, wrestling mats, are made of 4.2 cm (1.25”) thick rubber nitrile foam that includes a flame retardant in compliance with American Society for Testing and Materials (ASTM) standards [13]. Polyurethane foam is a complex material designed and manufactured with variable density, weight, stiffness, and cushioning characteristics. The loose foam pit, filled with polyurethane foam, has been used by thousands of gymnasts since the inception of the technology dating to at least the 1970s [14].

Polyurethane foam is a plastic material formed by combining a polyol with an isocyanate compound. Polyurethane foam requires a blowing agent to enhance its ‘fluffiness’ which provides the material with its softness and shock absorbing characteristics. Put simply, polyurethane is composed of a chain of organic molecular complexes joined by chemical links. The blowing agents were historically made previously from chlorine-containing mixtures, such as trichlorofluoromethane, but were replaced with carbon dioxide and water due to concerns regarding CFCs and atmospheric ozone depletion. Blowing agents give polyurethane foam its open-cell structure that markedly increases flammability by virtue of the large surface area that exposes a large amount of flammable material to an open flame. Thus, flame retardants have been used widely in polyurethane foam and other plastic-based flammable products.

So What Happens Over Time?

Foam materials deteriorate over time. Both age and exposure to light influence the rate of foam decomposition. Foam pieces deteriorate and crumble because of air exposure and mechanical compression and abrasion. The dust particles that arise from deteriorating foam can be purveyors of flame retardants that are inhaled and swallowed [3,15,16]. Moreover, flame retardant chemicals are known to ‘off-gas’ from the foam, both new and old, independent of physical degradation from wear [17].

Although PentaBDEs were phased out in 2004, a number of other chemicals have been identified as replacements [1,2]. Two of these replacements, chlorinated-Tris and Firemaster 550, were identified in newly purchased gymnastics pit foam; [1]. These replacements are also considered potentially hazardous to health and are being phased out of use in polyurethane foam [18,19].

One standard in particular, the California Technical Bulletin 117, has driven the use of flame retardants as additives to polyurethane foam used in residential furniture. Controversy surrounding this standard was recently covered in a series of stories by the Chicago Tribune and in the HBO documentary ‘Toxic Hotseat’. Due largely to efforts by The Green Science Policy Institute, the California standard was recently revised to specify that the covering, rather than the foam, must meet an open flame test. This presents a potential solution as there are ways to manufacture coverings so that foam-containing products meet this standard without the use of additive flame retardants.

Who Knows About This?

The recent study of gymnasts has brought the use of flame retardants in foam equipment, as well as the potential health concerns, to the attention of the gymnastics community. The study focused on a small sample of female U.S. collegiate gymnasts and merits additional study of larger populations and demographics of gymnasts. For example, it remains unclear to what extent recreational gymnasts, coaches, or younger competitive gymnasts are exposed to flame retardants. It is also unclear how flame retardants used in gymnastics equipment, and the regulations driving their use, vary regionally or what intervention strategies would be most effective.

Revenge Effects and Gymnastics

In our modern world, ‘revenge effects’ arise frequently [20]. A revenge effect is an unanticipated consequence that results from a new product or policy. Foam products have been crucial in the conduct of gymnastics training and performance. Protecting gymnasts from falls has been a leading injury countermeasure that has been supported by the use of cushioning materials. However, the materials that have allowed such protections from falls may be involved in a revenge effect that amplifies exposure to an environmental pollutant. Future research is required to evaluate the extent of the problems of flame retardants in sports equipment. However, given the slow rate of research and research funding it is precautionary to begin taking measures to minimize contact with these chemicals.

Prevention and Checking Your Gym

Gymnasts and coaches can help reduce the amount of flame retardant that enters their bodies washing their hands after practice and before they eat. Gym owners can help protect gymnasts and coaches by promoting handwashing practices in the gym and seeking flame retardant free options when replacing equipment. Additive flame retardants are not the only way to improve fire safety in the gym. Vinyl fabric may be sufficient for most mats and naturally flame retardant covers such as nylon can be considered for flame retardant free pit cubes. The presence or absence of flame retardants in foam equipment can be verified free of cost by sending samples to the Gymnast Flame Retardant Collaborative (, an organization formed to facilitate collaboration between flame retardant scientists and the gymnastics community. You can join the collaborative to receive updates on the science and policy of flame retardants in gyms, provide feedback and get involved in future studies.



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Dr. Joshua Eldridge

About Dr. Joshua Eldridge

Dr. Joshua Eldridge has specialized in protecting gymnasts from injury. He is the inventor of The X Brace, and has developed a treatment protocol for Sever's disease and heel pain that has helped thousands of gymnasts throughout the world. Dr. Eldridge brings practical, easy injury care and prevention that can be done at home.