Are Recycled Rubber Mats Unhealthy?

2010-10-27

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What Are the Risks of Recycled Rubber

Many people have expressed concern about the use of recycled rubber. Recycled rubber comes from used tires, which many fear could harbor lead or other toxins. Concerns kicked into high gear in 2009 after the environmental advocacy group PEER (Public Employees for Environmental Responsibility) uncovered internal communications from the EPA that stated that the agency could not vouch for the safety of recycled rubber because there had not been enough studies done at that time.

So are recycled rubber mats unhealthy? Let’s examine the facts.

The Benefits of Recycled Rubber Mats

Recycled rubber mats are made from used tires that would otherwise wind up in the waste stream. Used tires can sit in a landfill for thousands of years without breaking down. There, the tires can catch fire, resulting in massive output of toxic smoke. Tire fires are difficult to extinguish, and tires can smolder inside the stacks for years at a time. In open dumps, they become a breeding ground for mosquitoes, which spread disease.

Recycling tires into materials like playground mulch and rubber mats reduces the number of tires that wind up in landfills by up to 90%.

Rubber mats and mulch on playgrounds lead to significant reductions in injuries as compared to wood mulch or concrete. According to one study, injuries were twice as common on wood mulch surfaces and five times as common on concrete.

Concerns Raised by Recycled Rubber

The use of recycled rubber raises justifiable concerns. The laundry list of volatile chemicals used it tires is alarming: benzene, toulene, arsenic, acetone and many others, plus heavy metals that include nickel, copper and cadmium. Older tires may contain lead, as well. Under lab conditions, scientists observed that these chemicals leached from recycled tires. However, there are important differences between the circumstances of these studies and how recycled rubber reacts during actual use:

Most studies involved submerging tire crumb in water-based solutions for days, weeks or months. On the average playground, the recycled rubber mat will not have that level of exposure to water.
The tire crumb in the studies was raw and unwashed. During the recycling process for turning tires into mats and playground mulch, all metal is removed from the tires, and the crumb is washed. These two steps eliminate a great deal of volatile compounds that would otherwise leach out of the rubber.

Results of More Recent Studies

In response to the concerns raised by earlier recycled rubber studies, a number of new studies have been conducted specifically addressing recycled rubber used in playgrounds. These studies replicate field results, which can be dramatically different from results obtained in lab conditions. In these studies, recycled rubber mats have been found safe.

The most recent is a two year long study done by four state agencies in Connecticut published in August of 2010. The studies measured leaching and off-gassing of chemicals during normal playground usage, during periods of heavy rain, and also in lab settings. While some volatile chemicals were found to be present in the air above the play surfaces, particularly in indoor play spaces where there is less air circulations, the levels were low. Their studies concluded that, while levels of volatile chemicals were slightly higher than what are known as background levels, they were not high enough to be considered a health risk. The only chemical that leached out of the fields at a level higher than what is considered acceptable was zinc, which is not considered dangerous to humans unless excess amounts are ingested.

Playing It Safe

While the levels of chemicals off-gassing from indoor play spaces was considered below the threshold where the chemicals are harmful, it is worth noting that indoor play spaces showed up to ten times as much volatile chemicals in the air. If you want to err on the side of caution, you may want to consider refraining from using recycled rubber mats indoors, where there is a minuscule but present danger that could deem recycled rubber mats unhealthy.

In outdoor playing conditions, however, field studies show that you can breathe easy knowing that your kids are safer using the mats than not.