U.S. Consumer Product Safety Commission (CPSC)
Description: Crumb Rubber was tested using the method described in 16CFR 1500.44 of the Federal Hazardous Substances Act For rigid and pliable solids ( A material is considered "flammable" if it ignites and burns with a self-sustained flame at a rate greater than .01 inches per second along its major axis.)
Summary: In each test reading, the crumb rubber had a burn rate significantly less than that required for it to be considered "flammable". Based on the testing results, the crumb rubber is considered non-flammable according to the requirements of the Federal Hazardous Substances Act. The Testing also documented that "Specimens were easily extinguished after the 60 second testing period."
TEMPERATURE COMPARISON STUDY
Description: Crumb Rubber and typical play sand were tested to compare the temperatures, under full sunlight, that would be encountered under normal use in a typical playground setting. Test bed dimensions were 16" x 24" x 3" deep and all readings were on a 30-minute average with an ambient air reading of 101 degree F.
Summary: In each test reading , the crumb rubber remained significantly cooler than the play sand by as much as 20 degrees.
Description: Crumb Rubber was immersed into a strong hydrochloric acid (an acid which is significantly stronger than stomach acid) PSI report NO. 486-40013-001.
Summary: If swallowed, it should not cause any acute or chronic problems. Short-term issues, such as upset stomach will be a function of the amount of rubber chips swallowed, they are eventually evacuated from the body just like any other non-digestible material. There was basically no reaction to the crumb rubber. The testing company attributed the .7% loss to the nylon/rayon fiber, but the rubber itself did not react to the acids. Therefore, the chance of digestion is very slim on the data collected.
MISCELLANEOUS TESTING RESULTS
Melting point: 234 degrees
Spontaneous Combustion (Flashpoint):<610 degrees F
Relative Density: 22.0 pcf minimum, 30.9 pcf maximum
Permeability: Coefficient of permeability, 1.2cm/sec when tested at 30.5pcf.
Ground Tire Rubber (GTR) is a non-hazardous, filled hydrocarbon polymer and is considered to be non-toxic, non-metallic and principally organic, carbon based material.
EPA's Compliance Monitoring Section states that rubber added to the soil is not hazardous. It is "inert and biodegradable, but won't break down for 25+ years.
In 1991, testing commissioned by the Rubber Manufacturer Association, shows that leachate from tire samples contained only a few metal and organic compounds. The concentrations of these metals and compounds were 1-3 times less than those proposed TCLP regulation and EPA primary drinking water standards.
In 1994, the EPA added recycled crumb rubber to its Comprehensive Procurement Guide (CPG).