Question from Lisa
Dear Debra,
More and more, I notice that shoe soles are advertised as being made from recycled rubber. Are there any health concerns you would have from wearing shoes made of this recycled rubber? I am guessing that the recycled rubber is most likely from car tires.
Do you have any information about this?
Many children’s playgrounds use shredded rubber tires as a bedding material to cover the ground.
Is this safe for children to play on?
Debra’s Answer
This is one of those cases where recycling is good for the environment, but the material being recycled isn’t so good for health.
A report called Artificial Turf: Exposures to Ground Up Rubber Tires – Athletic Fields, Playgrounds, Garden Mulch states that their lab tests on ground tires “contained volatile organic hydrocarbons (VOCs) with carcinogenic potential, which could be extracted from the crumbs in the laboratory. Health reports from workers in the rubber fabrication industry and in the rubber reclamation industry describe the presence of multiple volatile organic hydrocarbons, semivolatile hydrocarbons, and other toxic elements in the air. Studies at tire reclamation sites report the leaching of similar sets of chemicals into the ground water. Occupational studies document a spectrum of health effects, ranging from severe skin, eye, and respiratory irritation to three forms of cancer.”
In addition, a “second set of experiments tested the chemicals released from the tire crumbs used for “in-fill” and commercial rubber mulch. Ten metals were leached from the samples of tire crumbs and the tire mulch in the first experiment. Twenty-five chemical species were identified with 72% to 99% certainty in the mass spectrometry and gas chromatography analysis in the second experiment. Nineteen were identified with over 90% certainty and five with over 98% certainty. Confirmatory studies provided a definitive identification of four of the major chemicals released.”
So I’d say, no, not safe for children to play on.
Most of the shoes online(especially dress shoes) seem to use recycled rubber soles. Is this ok to make an exception to buy these? Everything else such as the uppers and insole is non toxic.
It’s very difficult to find shoes made without synthetic rubber soles. There has been a good amount research that shows recycled rubber can offgas toxic chemicals. If you can’t find more natural alternatives, leaves them in a garage or outside rather than storing them in a closet.