The capsules are safe and easy to handle, and after they react the only byproducts are environmentally friendly, such as sand or sodium silicate, "which is the main ingredient in toothpaste," Lefenfeld said.

Sodium, potassium and other alkali metals are potentially extraordinarily useful elements because they are highly chemically reactive. However, this also makes them dangerously volatile.
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One exciting possibility for these capsules is generating hydrogen gas for vehicles in the future. Combining hydrogen gas with oxygen results in energy and water, and none of the dirty mix of toxins and global warming gases burning gasoline spews forth. The cleanliness of hydrogen is in large part why government and industry support for hydrogen vehicles has reached into the billions of dollars.

Scientists worldwide are experimenting with cost effective and convenient sources of hydrogen. The U.S. Department of Energy requirement for hydrogen production for 2015 is a material that can generate 8 weight percent hydrogen, "so if you put in 100 grams of a material, you're supposed to get eight grams of hydrogen back," Lefenfeld said. "Our materials currently can get up to 9 weight percent hydrogen, exceeding the 2015 requirement, with the potential of achieving 13 or 14 weight percent hydrogen which is nearly double the DoE 2015 requirement."
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Read the whole article at the link above.