An unfolding technology has increased our economic strength and added to the convenience of our lives. But that same technology-we know now-carries danger with it. From the great smoke stacks of industry and from the exhausts of motors and machines, 130 million tons of soot, carbon and grime settle over the people and shroud the Nation's cities each year. From towns, factories, and stockyards, wastes pollute our rivers and streams, endangering the waters we drink and use.