There is probably a greater risk of release of NBC's by government or industry than by terrorists, as recent history has shown. Setting limits on the scope of risk assessment is not a sound risk management approach.
Why the contribution is important
There are three types of risk/threats that need to be proactively planned for manmade, natural, and technological. There is no mention of the threat of technological hazards here, and in the digital age these may be the greatest threat.