7/28/2010

Yellowstone National Park hosts up to 3 million visitors each year, so park rangers have to work to minimize their guests' environmental impact. Every week, rangers collect hundreds of used propane tanks, and use a cutting-edge recycling facility to purge leftover fuel and flatten the cylinders for recycling as steel. The program has been so successful that rangers are working on a program to recycle used cans of bear repellent.

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