The US Department of Justice (DOJ), as part of its Body Armour Safety Initiative testing, has announced that test results indicate that used Zylon-containing body armour vests may not provide the intended level of ballistic resistance. As a result, DOJ will adopt new interim requirements for its body armour compliance testing programme, and will add an additional $10 million to the $23.6 million already available to law enforcement agencies through DOJ's Bulletproof Vest Partnership (BVP) programme to assist in the replacement of Zylon-based body armour vests.

NIJ performed ballistic testing on 103 Zylon-containing used armour vests from law enforcement agencies across the United States. Of these vests, 60 (58%) were penetrated by at least one round during a six-shot test series. Of those that passed penetration testing, 91% showed excessive "backface deformation," an indicator of the potential blunt trauma experienced by an officer wearing the armour. Only four used armour vests tested met all performance criteria under body armour standards for new body armour.

In response to the findings, the Japanese maker of Zylon fibre, Toyobo, said that it had not   had the chance to examine the underlying data supporting the report but that it was confident that it had acted in a responsible and transparent manner.