Name: Fly-Ash Brick
Inventors: Henry Liu
Cost to Develop: $600,000
Time: 20,000 hours
Prototype | | | | | Product

The U.S. churns out nine billion clay bricks a year-every one of them an expensive environmental nightmare. They require costly mining and bake in 2,000�F kilns that guzzle fuel and spit out pollutants. And making cement for concrete bricks spews thousands of pounds of poisonous mercury into the air annually.