Photos: Sniffing out poisons in products

One of these yellow bags from a popular clothing store is not like the other. Can you tell which one is laced with lead?

XRF machines can. They detected lead in jewelry and children's toys made in China last year, spurring massive recalls. Scientists use the X-ray fluorescence technology to sample all sorts of raw materials. It is enlisted increasingly by government and watchdog groups to test consumer goods and packaging, including electronics components and casings.

The California Department of Toxics Control showed how the process works Tuesday at the Green Manufacturing Expo in Anaheim, Calif.

As a growing number of imports from China proved to be toxic over the past few years, the U.S. Consumer Product Safety Commission has stepped up product recalls.