Which table of distances do I use when storing blasting agents or ammonium nitrate near high explosives or other blasting agents?

When storing high explosives (HE) near blasting agents (BA)

  • Calculate distance using table 555.220, with HE as the donor.

  • Calculate the distance using 555.218, with BA as the donor.

  • The more restrictive of the two distances is the minimum required distance between magazines of HE and BA.

  • Use table at 555.218 to determine required distance to inhabited buildings, highways and passenger railways.

  • When determining minimum required distance from detonator storage to BA storage, the detonator magazine is always the donor. (Only the table at 555.220 may be used for this calculation.)

When storing blasting agents (BA) near other BA

  • Use only the table at 555.220.

  • The weight (row) to be used is based upon the donor material (the greater amount).

  • The column to be used (BA) is based upon the acceptor material.

  • Multiply the distance by 6 when unbarricaded.

When storing high explosives (HE) or blasting agents (BA) near ammonium nitrate (AN)

  • HE or BA to AN storage: use 555.220 with AN as the receptor—AN alone is never the donor.

  • Combine ½ the weight of the AN (with the donor) if the distance from the HE or BA to AN does not meet minimum separation distance.

  • Multiply minimum distances in table 220 by 6 when the AN or BA are not barricaded.

ATF has issued an open letter to addresses issues such as BA storage near HE, BA or AN and how to determine which storage magazine is the “donor” and which is the “acceptor” when applying the tables of distances at 27 CFR 555.218 and 27 CFR 555.220. Industry members who store blasting agents or ammonium nitrate should read the complete open letter at https://www.atf.gov/rules-and-regulations/explosives-open-letters.

Last Reviewed October 4, 2018