placard or lettering in letters not less than 3 inches high on a contrasting background: Provided, however, that if such articles are, because of size and kind of containers, exempted from the packaging, marking, and labeling requirements of Part 73, and provided such exempted commodities do not have a gross weight (contents and containers) exceeding 5,000 pounds, the provisions of this subparagraph shall not be applicable.

77.841. Poisons.

Subpart B.-Loading and unloading

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(d) Radioactive material.-A container of radioactive material bearing radioactive material, red label, must not be placed in vehicles, terminals, or other places closer than 3 feet to an area which may be continuously occupied by passengers, employees, or shipments of animals. When more than one such container is present, the distance from occupied areas must be computed from the table in subparagraph (1) of this paragraph by adding the number of units shown on labels on the containers.

(2) Not more than 40 units of radioactive material, red label, shall be transported in any vehicle or stored in any location at one time. Packages must be so blocked or braced in vehicles as to prevent any shift of lading under conditions normally incident to transportation.

Subpart D.-Vehicles and shipment in transit: Accidents

77.860. Accidents; poisons:

(d) Cleaning vehicles.-Any motor vehicle which, after use for the transportation of radioactive materials in truckload. lots, is contaminated with such materials to the extent that a survey of the interior surface shows that the beta-gamma radiation is greater than 10 milliroentgens physical equivalent in 24 hours or that the average alpha contamination is greater than 500 disintegrations per minute per 100 square centimeters shall be thoroughly cleaned in such a manner that a resurvey of the interior surface shows the contamination to be below these levels. A certificate to that effect must be furnished the carrier or to the driver of the motor vehicle. Motor vehicles which are used solely for the transportation of radioactive materials are exempt from the provisions of this section.*

*Revised May 3, 1955.

Subpart E.-Regulations applying to explosives or other dangerous articles on motor vehicles carrying passengers for hire

77.870. Regulations for passenger-carrying vehicles:

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(g) Radioactive materials on passenger-carrying vehicles.-No motor carrier may transport any radioactive material, poison, class D, requiring red or blue radioactive material label under these regulations in or on any bus while engaged in the transportation of passengers except where no other practicable means of transportation is available. Packages of radioactive materials must be handled and placed in the vehicle in accordance with the requirements of 77.841 (d) of this part.

Chapter III

CIVIL AIR REGULATIONS GOVERNING THE TRANSPORTATION OF RADIOACTIVE MATERIALS

The transportation of radioactive materials by air is regulated by the Civil Aeronautics Board. Its Civil Air Regulations covering the Transportation of Explosives and Other Dangerous Articles constitutes Part 49 of Title 14 of the Code of Federal Regulations. Those regulations of particular interest to shippers of radioactive materials are excerpted below.

Many of the Civil Air Regulations applying to the shipment of radioactive materials-especially those applying to packaging, marking, or labeling of such materials are based on ICC regulations. Comments made in Chapter II on ICC regulations are not repeated here. The few comments made in this chapter are distinguished from the text of the excerpts as in Chapter II. Limitations on the nature of these comments are given on page 1, Chapter I.

Part 49.-Transportation of Explosives and Other Dangerous Articles 49.0 Applicability of part:

Explosives or other dangerous articles, including flammable liquids, flammable solids, oxidizing materials, corrosive liquids, compressed gases, and poisonous substances, shall not be loaded in or transported by civil aircraft in the United States, or transported anywhere in air commerce in civil aircraft of United States registry except as hereinafter provided.

49.1. Definitions:

(a) As used in this part the words listed below shall be defined as follows:

7 (iv) Radioactive materials-Class D.-A radioactive material is any material or group of materials which spontaneously emits ionizing radiation. For the purpose of these rules, radioactive materials are divided into three groups according to the type of radiation emitted at any time during transportation as follows:

(I) Group I radioactive materials.-Group I radioactive materials are those materials which emit any gamma radiation, either alone or with electrically charged particles or corpuscles.

(II) Group II radioactive materials.-Group II radioactive materials are those materials which emit neutrons and either or both of the types of radiation characteristic of Group I radioactive materials.

(III) Group III radioactive materials.-Group III radioactive materials are those materials which emit only electrically charged particles or corpuscles (i. e., alpha and/or beta radiation).

The above definitions of Group I and Group III materials differ slightly from the ICC definitions. (See 73.391 (a), page 12.)

(8) "Unit" of gamma radiation. "Unit" of gamma radiation is one milliroentgen per hour at a meter for "hard gamma" radiation, i. e., that amount of gamma radiation which will have the same effect on sensitive photographic film as one milliroentgen per hour at a meter of "hard gamma" radiation of radium filtered through 1/2 inch of lead.

See page 16 for comments on filtration of radiation.

(10) Cargo aircraft. A cargo aircraft is an aircraft other than a passenger-carrying aircraft which is carrying goods or property.

(11) Marking. Marking is the display on the container of the name of the articles inside as listed in the commodity list of the ICC Regulations.

(12) Labeling. Labeling is the display on the container of an appropriate label as specified for a particular class of articles by the ICC Regulations.

(13) ICC Regulations. ICC Regulations shall mean the "Interstate Commerce Commission's Regulations for Transportation of Explosives and Other Dangerous Articles," effective January 7, 1941, as amended or revised from time to time.

(14) Aircraft operator. An operator of aircraft shall include the owner, lessee, or any other person who causes or authorizes the operation of the aircraft.

49.3. Packing, marking, and labeling requirements:

(a) Unless otherwise specifically provided in this part, explosives or other dangerous articles shipped by air shall be packed, marked, and labeled in accordance with the specifications established in Part 72 of the ICC Regulations for transportation by rail express: Provided, That liquids shall be packed only in containers which are securely closed, sufficient strength to prevent any leakage or distortion of the containers caused by change in temperature or

4 Part 72 of the ICC Regulations incorporates the packaging specifications of Part 73 thereof. It will be noted that items exempted from the packaging, labeling, or marking provisions of Part 73 of the ICC Regulations are not exempted from such requirements for shipment by air unless it is expressly so provided in this part.