According to the article, prisons in United States will adopt iris scanning systems on site to prevent inmate escapes, which recently happened at a prison in Baltimore.

The whole project will be assisted by the US Government, to install iris scanners as well as building a biometric data base of inmates around the country. Besides iris scanning technology, fingerprint scanning is also critical in law enforcement since iris will break down significantly after death and this is when fingerprint biometrics proves its role.  

Source: thirdfactor, Prisons turning to biometrics for inmate release (1 Mar 2010)