Radiocarbon levels in teeth formed before then contained less radiocarbon than expected, so when applied to teeth formed during that period, the method was less precise.

Now, new applications for the technique are emerging in forensics, thanks to research funded by NIJ and other organizations.

In recent years, forensic scientists have started to apply carbon-14 dating to cases in which law enforcement agencies hope to find out the age of a skeleton or other unidentified human remains.

However, more testing is needed to confirm that belief. 269, March 2012NCJ 237722 Philip Bulman is a writer and editor at NIJ.

Danielle Mc Leod-Henning is a program manager and physical scientist at NIJ.

Thus, pupal case radiocarbon content would serve as a decay-resistant proxy for the tissues, yielding the year of death.

The spike in atmospheric carbon-14 levels during the 1950s and early 1960s makes this approach possible, but it also means it will have a limited period of utility because the amount of carbon-14 in the atmosphere is slowly returning to its natural level.

However, the researchers suggested that soft tissue radiocarbon content would be transferred to, and preserved in, the pupal cases of insects whose larvae feed on these tissues.

Such insects are simply another link in the food chain.

Barring any future nuclear detonations, this method should continue to be useful for year-of-birth determinations for people born during the next 10 or 20 years.

Everyone born after that would be expected to have the same level of carbon-14 that prevailed before the nuclear testing era.

Unlike tooth enamel, soft tissues are constantly being made and remade during life.