First responders are among those whose lives depend on body armor — and the ballistics fibers inside them. (Credit: Shutterstock)

Scientists at the National Institute of Standards and Technology (NIST) have developed a new way to investigate the high-performance fibers used in modern body armor. The testing of soft body armor has been a big concern because the deployment of a new kind of fiber — believed to be superior to the previous material — unexpectedly failed in 2003, resulting in the death of a police officer. That and other incidents prompted a 2005 recall of some of the vests made with the new material.

While the degradation in the mechanical properties was self-evident, what was missing was an analytical technique to characterize the structural or chemical differences in the fibers that would account for their loss in performance.