The U.S. Department of Homeland Security (DHS ) has issued a proposed rule that would restrict the sale, purchase and transfer of ammonium nitrate, a common component of fertilizer that has been used in the manufacture of bombs. 76 Fed. Reg. 46,908 (8/3/11). Under the plan, ammonium nitrate would be defined to include any mixture that is 30 percent or more ammonium nitrate by weight.

The plan would allow only individuals approved by DHS to legally acquire the substance above a threshold level. Owners or operators of ammonium nitrate facilities and those intending to purchase the substance would be required to register with DHS and provide the agency with the names of their agents. Sellers would be required to retain records and report theft or loss of the substance to the agency within 24 hours.