Ammonium Nitrate P r o b l e m Discussed . A I M I N G at coordinating all efforts to ward evolving safe methods of handling ammonium nitrate, more t h a n 120 persons representing groups vitally interested in the manufacture, storage, handling, ship ment, and use of ammonium nitrate gath ered in Washington, D. C , recently to discuss fire hazards connected with han dling the chemical. T h e meeting was held in conjunction with the President's Con ference on Fire Prevention, and was under the chairmanship of M a j . Gen. Philip B. Fleming, administrator of the Federal Works Agency. T h e first two speakers, M a j . Gen. E . S. Hughes, chief of Ordnance, and Col. H. T. Miller, Transportation Corps, both con sidered ammonium nitrate a relatively safe material to handle. Gen. Hughes felt that it was the unusual conditions existing aboard ship—co' finement of ma terial, large tonnages, and difficulty of combating fires—which must be considered in the formulation of regulations for tin? control of ammonium nitrate. Col. Miller warned against making un necessary restrictions which would in crease the cost of handling and transporta tion of this material which is so important to the agriculture of t h e world at the pres ent time. He believed that exercise of good common sense and enforcement of existing rules would completely eliminate the hazard of handling and transporting ammonium nitrate. Technical
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There is evidently much to be learned about the explosive n a t u r e of ammonium nitrate and several speakers spoke on the progress t h a t has been made in this di rection. A. C. Fieldner of t h e Bureau of Mines pointed out t h a t ammonium ni trate, when used as an .explosive, invari ably contained a booster; however, re search conducted as a result of the Texas C i t y disaster had revealed t h a t under suitable conditions of confinement the material would detonate without a booster (see C & E N , p. 2143, July 28, 1947). Dr. Fieldner added t h a t the bureau was con ducting further work along these lines in order to help meet the need for general research in this field. T h e various combinations of a m m o n i u m n i t r a t e and other materials t h a t are used a s fertilizers were discussed by R. Ο. Ε . D a v i s of t h e D e p a r t m e n t of Agriculture with emphasis on t h e explosive character of these mixtures, pointing out t h a t the organic matter which is added to prevent t h e caking of a m m o n i u m nitrate definitely increases t h e danger of explosion. Other combinations, particularly those with cal cium carbonate, are much safer. H e also highlighted the importance of a m m o n i u m n i t r a t e to the agricultural economy by
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pointing out t h a t a t least 4 0 % of the ni trogen fertilizer used as top dressing was furnished by ammonium nitrate. Somewhat a t variance with Dr. D a v i s ' statement was the information furnished by Bernard Lewis of the Bureau of Mines that the British h a d shown t h a t a fiftyfifty mixture of ammonium nitrate a n d calcium carbonate was explosive. Dr. Lewis also added t h a t various materials, such a^ chromium compounds, finely di vided carbon, iron compounds, etc., act as catalysts for the decomposition of a m m o nium n i t r a t e to give acids which in t u r n make t h e material more susceptible to ex plosion. H e further declared t h a t investi gations of the explosions a t Texas City a n d Brest, France, had revealed t h a t both could have been prevented in all probabil ity if reasonable safety rules had been ob served in the handling of ammonium ni trate. A previously unreported a m m o n i u m nitrate explosion which took place a t Tessenderloo, Belgium, during the Ger man occupation in 1942 was described b y M at hew Braidech of the National Board of Fire Underwriters. I n this instance t h e material appears to have exploded spon taneously and at present there are no good theories as to its cause. Railroad
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W. G. M c K e n n a , chief chemist of the Bureau of Explosives, American Associa tion of Railroads, spoke briefly about t h e experience railroads have had in the t r a n s portation of a m m o n i u m nitrate. In the last three or four years some 10 or 12 fires have occurred in boxcars containing a m m o n i u m nitrate, but in no case has an explosion occurred, Dr. M c K e n n a stated.
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H e further explained t h a t all-steél boxcars are not u s e d for this purpose; therefore, t h e confinement factor usually present aboard ship is not a problem. H e did not feel that a m m o n i u m nitrate was a p a r ticularly dangerous material t o t r a n s p o r t by rail; however, t h e railroads a r e continuing their research to determine t h e best conditions for rail transport. Billings Wilson, president of the P o r t of New York A u t h o r i t y , after a lengthy discussion of t h e problems encountered b y t h e port in h a n d l i n g a m m o n i u m n i t r a t e , suggested t h a t m a t e r i a l s of this n a t u r e be handled in isolated ports in order t o minimize t h e n u m b e r of persons likely to b e involved in a n y explosion. Louis Johnson, former Undersecretary of War, discussed the legal aspects of p u b lic safety regulations and control measures affecting handling a n d t r a n s p o r t a t i o n of a m m o n i u m n i t r a t e . I t was pointed o u t t h a t as much d a t a as possible from a c t u a l explosions is of great importance in court cases. Although t h e assembled group had n o a u t h o r i t y to m a k e binding regulations, i t did bring together people of a wide varie t y of interests who could freely exchange information o n this i m p o r t a n t subject. T o aid in carrying on the work a five-man committee k n o w n as the A m m o n i u m N i t r a t e C o m m i t t e e of the President's Conference on F i r e Prevention, was a p p o i n t e d under the c h a i r m a n s h i p of Billings Wilson. T h e other four members of t h e c o m m i t t e e a r e : R. O. E . D a v i s ; Warren W a t s o n , secretary of t h e M a n u f a c t u r i n g C h e m i s t s ' Association; Commodore H . C. S h e p heard, U. S. C o a s t G u a r d ; and M a the w M . Braidech.
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