They measured carbon-14 levels in various tissues from 36 humans whose birth and death dates were known. The researchers found that certain soft tissues — notably blood, nails and hair — had radiocarbon levels identical to the contemporary atmosphere.

What can be carbon dated?

Samples that have been radiocarbon dated since the inception of the method include charcoal, wood, twigs, seeds, bones, shells, leather, peat, lake mud, soil, hair, pottery, pollen, wall paintings, corals, blood residues, fabrics, paper or parchment, resins, and water, among others.

Can charcoal be carbon dated?

Any charcoal or wood sample that is carbon dated will have an apparent age, which may result in errors of up to hundreds of years unless short-lived tree species or twigs are selected for radiocarbon dating.