Cesium as Limited Quantity

Your facsimile transmission dated November 18, 1998, to the Office of Civil Aviation Security, Federal Aviation Administration, has been referred to this office for reply. You ask about international shipping requirements for an atomic clock that contains 2 grains (0.07 ounce) of cesium in a vacuum metal container.

The International Air Transport Association's (IATA) Dangerous Goods Regulations do not have official standing under the U.S. Hazardous Materials Regulations (HMR; 49 CFR 171-180). The regulations recognized by the HMR and authorized in 49 CFR 171.11 as an alternative to compliance with 49 CFR requirements are the International Civil Aviation Organization's (ICAO) Technical Instructions.

Neither the ICAO Technical Instructions nor the HMR provide limited quantity packaging exceptions for cesium. All shipments of cesium, no matter how small, must be packaged in UN or DOT specification packaging that is properly marked as such. Section 173.211 of the HMR specifies the packaging requirements for non-bulk shipments of Packing Group I hazardous materials. For combination packagings, this section provides that Packing Group I hazardous materials such as cesium may be packaged in a metal receptacle contained inside an authorized outside packaging such as a 4A steel box or a 4D plywood box. The outside packaging must be marked in accordance with § 178.3 of the HMR.

You may wish to consider seeking an approval for your shipment under § 173.4 of the HMR. This section authorizes small quantity exceptions for certain classes of hazardous materials. Paragraph (c) permits packages of Division 4.3., Packing Group I materials that conform to the quantity and packaging requirements listed in paragraphs (a)(1) through (a)(10) of § 173.4 to be offered for transportation if specifically approved by the Associate Administrator for Hazardous Materials Safety. Enclosed is a sheet outlining in plain language the procedures necessary for RSPA's Associate Administrator to grant an approval.