Approximately 11 million tons (10 million metric tons) of asphalt-shingle waste is generated annually in the U.S., according to a report by Sengoz and Topal published in 2005. The majority of this waste ends up in landfills. In fact, Jon Powell of Innovative Waste Consulting Services, Gainesville, Fla., says that less than 10 percent of asphalt shingles actually get recycled, leaving a whopping 10 million tons (9 million metric tons) behind to clog landfills.

Asphalt, a petroleum-based product, is highly toxic and pollutes during manufacture, use and disposal, according to The Sustainability Project, part of the Santa Barbara, Calif., Green Building Guidelines. Furthermore, even alternative polymer-based membrane roofing is made from a petroleum- derived material. While exact figures are not readily available, Katie Janess, associate partner at Ducker Worldwide, Troy, Mich., estimates that more than 3 billion square feet (279 million-m2) of flat roofing (membrane and built-up) also finds its way to landfills.

To put these numbers in perspective, consider the fact that 3 billion square feet (279 million-m²) is the equivalent of 115 square miles (298 km²) of membrane per year—enough to cover the island of Manhattan more than four times. If you add the estimated 10 million tons (9 million metric tons) of asphalt-shingle waste generated annually to the figure, you’d have more than 21 Manhattan-sized tarps. The combined 493 square miles (1277 km²) is the equivalent of a standard two-lane highway 129,880 miles (209022 km) long. That highway could encircle the planet five times.

Considerable time and resources have been allocated to recycling efforts with many petroleum-based roofing materials. However, the processes often are difficult and potentially hazardous. In fact, in some states, recycling of tear-off shingles is banned entirely because it can be a health risk to workers handling the material. Until these products can be recycled safely and at a higher rate, their use should be limited.