By Raleigh McElvery, special to C&EN
In 1999, a lightning storm ignited 7 million scrap tires piled on the slopes of a canyon near Westley, California. A near-apocalyptic scene erupted, according to a 2001 US Environmental Protection Agency case study on the incident .
A 60 m roaring “fireball” and “tornado-like vortex” propelled smoke hundreds of meters into the air, spewing soot as far as 100 km away. The blaze was finally extinguished 5 weeks later, but not before it devastated surrounding land, spread noxious emissions, and discharged massive volumes of oil from the melted rubber.
Scrap heaps like these constitute a portion of the more than 50 million waste tires that California generates annually. Those that end up in landfills not only pose fire hazards but also release pollutants and breed pests like mosquitoes. To divert waste tires from such deleterious ends, states like California and some countries around the world have come to a common conclusion: this rubber should meet the road.
A 1991 US federal law, the Intermodal Surface Transportation Efficiency Act, required all state departments of transportation (DOTs) to start adding rubber to a prescribed portion of their federally funded roads. However, the technology for doing so wasn’t ready, and the […]
Credit: JK Jeffrey/Shutterstock
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