border security

Criminals are smuggling an estimated $30 billion in U.S. currency into Mexico each year from the United States, but help could be on the way for border guards, researchers reported recently. The answer to the problem: a portable device that identifies specific vapors given off by U.S. paper money.

Sandia National Laboratories researchers want airports, border checkpoints and others to detect homemade explosives made with hydrogen peroxide without nabbing people whose toothpaste happens to contain peroxide.