At a greatly increased level of threat, the recommended actions are those for which necessary technical capabilities are currently lacking or for which the costs at present are unwarranted, the inconvenience of implementation is too great, or the utility and applicability are too limited. Additional actions recommended at a greatly increased level of threat are as follows:
Considering the use of coincident gamma-ray marking of detonators and/or explosives;
Implementing an inerting technique for bulk fertilizer-grade ammonium nitrate if technically feasible, agriculturally suitable, and economically acceptable methods are found as a result of future research and development efforts; and
Requiring licenses for sellers and permits for purchasers of bulk and packaged detonable nitrate-based fertilizers, sodium nitrate, potassium nitrate, nitromethane, concentrated nitric acid, concentrated hydrogen peroxide, sodium chlorate, potassium chlorate, and potassium perchlorate. The alternative would be to ban sales of specific precursor chemicals in certain markets.