PREVENTION OF ACCIDENTS WHEN HANDLING CHEMICALS RUDOLF WINDERLICH Oldenburg im Oldenburg, Germany Translated by Ralph E. Oesper The days of our years are threescore years and ten; and if by reason of strength they m y be fourscore years, yet i s their strength labor and sorrow, for it i s soon cut off and
we fly away. Psalms X c, 10
TEE upper limit of the lifespan, which the psalmist assumes, is reached by relatively few: sickness and accidents sometimes hurry even the able-bodied into their graves. The constant progress of medicine has considerably reduced one of these causes of premature death. However, many believe that we are helpless against the apparently haphazard accidents, because they almost always occur unexpectedly. Nevertheless, the toll of accidents can also be decreased. Even the most experienced of us should always be conscious that we, too, are not entirely immune to serious accidents, which may be the consequence of our own or another's ignorance, carelessness, blunders, or indifference. During a lecture by Justus Liebig before a selected audience in Munich he exhibited the strikingly beautiful combustion of carbon bisulfide in nitric oxide. The delight of the onlookers led him to repeat the demonstration. This time, to the great horror of all present, there was a terrific explosion, the flask was shattered into bits. Queen Therese, Prince-regent Luitpold, and Liebig himself were seriously wounded by the flying glass. The accident would have been fatal for Liebig if his snuff box had not prevented a large splinter of glass from penetrating his femoral artery.' On August 14, 1810, Berzelius wrote to Gehlen: "Since my last letter I have been temporarily blinded because of an explosion of fulminating gold, and I barely missed losing my sight entirely. This happened on March 5, and I still was not able to read by the end of A ~ r i l . " ~The recipient of this letter, Adolph Ferdinand Gehlen, died in Munich on July 15, 1815, after eight days of horrible suffering. He had been working with arsine and because he was not aware of its toxicity had taken no precautions against breathing this deadly gas. These examples show that even the most skilled experimenter is not immune to accidents. Much less so are young people, who l i e to do experiments, or factory workers, who pay no heed to the possible dangers, or 1 Letter of Liebig to Wohler, April 18, 1853. "Briefwechsel," vol2, p. 11. Schweiggem JournalftZr ChemieundPhysik,1,257 (1811).
laymen, who have no chemical knowledge and often regard it as superfluous. A remarkable verdict handed down by the German Supreme Court against a druggist because of a serious injury received from potassium chlorate led the writer to ask a group of presumably well-educated gentlemen: "What is potassium chlorate?" Of the twelve, only four knew the material, namely a chemist, a physician, a school principal, and a clergyman, while significantly, the two jurists present .dated that they had never even heard the name.' POISONS
As the son of an apothecary, Gehlen, from boyhood on, was familiar with chemicals, but be nevertheless fell a victim to an insidious poison. Everyone is exposed to similar dangers if he is ignorant of them. No layman t h i s of soot as harmful, and yet as early as 1775 the English surgeon Percival Pott found that it could be held responsible for the skin cancers so often contracted by chimney ~ w e e p s . ~A century later, R. Volkmann proved that tar was the actual carcinogenic agent, that it attacks tar workers and blast furnace operators.' Subsequently, the Frankfort surgeon L. Rehn traced the mysterious cancer of the bladder of aniline workers back to the inhalation of aniline vapors, or to the constant handling of fuchsine and p-naphthylamine.' Since then many carcinogenic materials have been uncovered. Now that the relation is known, exposed persons are constantly guarded and tested for susceptibility. Not all persons are equally receptive to diseases; the susceptible ones must be removed in time and the permanent workers must be replaced a t proper intervals by others who are also immune. a WLNDERLICA, R., "Chemisehe Kenntnisse ausserhalb der Fachkreise" in Der Deutsche Chemiker, Beilage sur, 2.angeu. Chem., 53. Berthelot discovered potassium chlorste in 1786. It was tried a t once in powder manufacture. No l a k r than October, 1788,two men were killed a t the Essone powder factory, in an explosion which might easily have cost Lavoisier his life. 'Porn, PERCIVAL, L'Chirurgicd observations relative to the cancer of the scrotum," London, 1775. 6 "Beitriige zur Chinugie," Leipeig, 1875. a Archiu fur klinische Chirurgie,50,588 (1895).
630
DECEMBER. 1950
.
671
Phenol, formaldehyde, and ally1 mustard oil damage it was found that the toxic material was also absorbed the skin; after long exposure they destroy the skin tis- through the skin, with the result that paralysis occurred sue. Likewise, carbon bisulfide, paraffin, and olefines after wearing skirts, coats, etc. fashioned from this fabare not entirely harmless if they act on the skin continu- ric, t,he 0. T. was replaced by a safe plastici~er.~' It ously. In the hygienic supervision of all industries spe- has happened repeatedly that synthetic materials which cial care must be given to supersensitivity, which is not at first appeared to be highly advantageous have had to always an inborn characteristic hut is often acquired as be abandoned for many purposes. For instance, the a result of frequently repeated exposure. H. S. Mart- German army used a cap lining that had been impregland found that the salts of radium, mesothorinm, and nated with phenolic resins. I t was fonnd that thest. radiothorium were responsible for bone cancer among resins decomposed t.o an extcnt which, t,hough scarcely those employed in making luminous timepieces.' These noticeable, was sufficient t,o release enough phenol to women pointed between their lips the fine brushes wit.h produce skin damage. The caps were called in and t,he which they applied the radioactive mass to t,he dials. linings replaced.12 This custom has of course now been prohibited. The Far-sighted governments have issued warnings and danger from radioact,ivcmat,erialscould have been fore- passed laws to protect the public against poisonous maseen much earlier, because Sir William Ramsay died in torials. These regulations are being constantly ex1916 of nasal cancer cont,ract,edfrom his long continued t,ended and improved. Households have been forhidwork with intense radium radiat.i~n.~ den to store coal oil. hensene, henzine, turpentine, Among the long-known heavy poisons, lead and rar- wood alcohol, hydrochlorir acid, et.v., in old beer or wine ban monoxide are the most frequent industrial health bot,tles, because people have oft,en been poisoned hazards. The list is being constantly lengthened and through mistaking such liquids for the original contents an additional toll of life and health is often taken before of the bottles. Laws have been enact,ed for supervising the effectsare recognized and measures taken to guard t,hetrade in foods and other necessities. against the careless handling of toxic or noxious mateIt should be a strict reqnirement that e v e v educarials. A striking example is ortho tricresyl phosphate t,ional institution, from the lowest school to the univer(CsH&H3)&0' 4, which has brought misery to many sity, must store its chemicals in such a manner that persons in Germany. This compound is employed in unauthorized persons have no access to heavy poisons, industry as a softener for plastic masses, as a solvent for which should, in addition, be kept in tight containers. gums and-mixed with acetone-as a polishing agent. Care should be exercised in storing even "harmless" During the period when fats were very scarce in Ger- chemicals. For instance, alkalies and alkaline submany black marketeers sold this nice-looking clear oil stances should not be put into bottles fitted with ground to the hungry public for cooking purposes. Its inges- glass stoppers, since deliquescence and the resulting tion results in psychic disturbances and temporary or cementing of the stoppers often makes it impossible to permanent paralysis. The extreme danger is evidenced open the bottle without shattering the glass. Someby the official report of the situation that arose in Gel- times accidents are caused by such frozen stoppers. A. senkirchen. The reporting physician states: "In our W. Hofmann reported the explosion of a 10-liter bottle city numerous cases of severe ortho tricresyl phosphate of chloride of lime, which had stood unused for 10 years (0. T.). ~oisoninrroccurred after linseed oil. inadvert- because the sto~wer * . could not be loo~ened.'~ ently contaminatled with 0. T., was used as salad oil , , , , ,, in a factory kitchen. A notable factor is the small Thoughtlessness or carelessness may expose buildings amount of 0. T. that brought about the poisonings. and entire blocks to violent explosions if remainders of Pure linseed oil was put into an empty barrel, which previously had contained linseed oil to which 0. T. had combustible volatile materials are dumped into drains been added. Consequently, i t was only the residual and thus get into the sewers. If, for instance, waste layer on the sides of the barrel that could still have con- oils from garages are run into the drainage system, they tained 0.T. The works personnel came down with vaporize there, and by an unfortunate combination of paralyses, which in part have not yet disappeared, even circumstances the resulting explosive gaseous mixture though some of the patients had eaten only one meal may be touched off. Consequently, before the war the (flour pancakes) which had been prepared with linseed garages and automobile laundries in Berlin were prooil taken from this barrel."9 Numerous cases of 0. T . vided with gasoline separators. More than one serious poisoning have occurred in the United States, where the fire or explosion has resulted in chemical laboratories from the careless custom of throwing all sorts of resimalady is known as ginger paralysis orjake leg.Io dues into the same waste can, where unexpected reaco-Tricresvl nhosnhat,n of ~~~- was formnrlv a, const,it.ilnnt, .-....--. .. the valuable synthetic textile known as Igelite. After may then
a
~
~~A~
~~~
' J. Am. Med. Assoc., 92,466, 552 (1929).
Reeardine the life and work of Sir William Ramsav see R e w t o f & ~ m & s a i a n l n s t i h d i n . 1919. DO. 531-546.
The Robert Koch Institut fiir Hygiene und Infektionskrankheiten (Berlin) investigated the problem thoroughly as to whether ~tricresylphosphate is ahsorbed through undamaged skin. The answer was in the affirmative. Deutsche medizinische Wochenschrift. 75.311 (1950).
JOURNAL OF CHEMICAL EDUCATION
672
As a matter of fact, unpleasant surprises may result from perfectly harmless procedures if proper precautions are not observed. When a warm concentrated solution of potassium nitrite is allowed to flow slowly into a similar solution of ammonium chloride, nitrogen is evolved.
-
storage, so that on the day of the disaster the explosive was acting chiefly on ammonium nitrate. It must he remembered moreover that the decomposition of ammonium sulfate-nitrate is exothermic: 2NH4NOr (NHJgSO,
-
8&0
t
+ SO. t + 3N2 t + 74.2 kg.-csl.
Perhaps the moral to he drawn is that caution is the order of the day whenever a uotential reaction is exoThe production of gas accelerates constantly because thermic. the reaction is exothermic, and with rising temperature I regret that I myself have not always acted with due the reaction rate increases exponentially. If the flask consideration. For many years I had my students is not cooled quickly by immersing it in cold water the carry out the synthesis of magnesium, calcium, and excessive gas pressure is liable to force the rubber stop- aluminum sulfide from the elements. However, in per out of the flask or the latter may blow up. May, 1927, a demonstration experiment before the class The possible serious consequences of not following with a tiny amount of powdered magnesium and flowers directions explicitly when carrying out a well-tested of sulfur produced a loud report; the test glass was procedure is strikingly illustrated by a horrible accident blown to hits, and the accompanying flame set fire to a which killed ten students and injured many more in the window shade six feet away. At this same time the chemistry laboratory a t the University of Miinster on authorities a t the University of Miinster called attenMay 27, 1920. The purpose of the experiment was to tion to the existing danger.16 The powdered magnedemonstrate combustion by means of bound oxygen; sium I had used hitherto was coarse grained, whereas the chosen reactants were cotton and tetranitrometh- the material that gave rise to the explosion was an imane, to which a little toluene was added since the carbon palpable powder and accordingly more reactive. Conof the cotton was not sufficient for the oxygen content of sequently, it is imperative to test new supplies of matethe oxidizing agent. According to the procedure, rials before using them in the presence of other persons. which had been tested repeatedly before previous As was the case at Oppau, the real causes of many exclasses, 15 grams of cotton were to be pressed into a plosions are never completely discovered. This apsteel tube (2.8 em. in diameter) and then moistened plies, for example, to the explosion that occurs occawith a mixture of 67.5 cc. C(N02)n and 7.5 cc. CeHsCHa; sionally when potassium is determined by the perchlothe moistened cotton was then ignited. Because of a rate method. Max Popp, Director of the Agricultural typographical error in the newly rewritten lecture Experiment Station a t Oldenburg, experienced a case of demonstration journal, the assistant used grams instead this kind which fortunately did notinjure anyone. Durof cubic centimeters of the liquids. The proper propor- ing removal of the excess perchloric acid by fuming the tions by weight are 108: 6. The experiment went along platinum dish was suddenly torn into fragments which as expected for three minutes, and then the frightful ex- were hurled through the air. Perhaps dust particles of plosion took place.14 organic nature or an unforeseen local superheating Intentional explosions as supporting attractions in brought about the sudden decomposition. Organic lecture course must not he carried out on too large a impurities are certainly the most frequent causes of such scale, since they can cause damage even though no one explosions", whereas the explosions during the boilingis visibly wounded. Lothar Meyer, who was very fond off of ether can usually he ascribed to peroxides, which of explosion demonstrations told of an experience with are formed on prolonged storing in the light.I8 acetylene in one of his lectures. "The explosion was The chlorates are much more dangerous than pera quite powerful one, and one of the students, who sat, chloric acid and the perchlorates. Numerous accidents rather far from the lecture table, reported to me lat,er have been due to potassium chlorate. Its victims have that after the bang he could see me talking hut could been not only students but even teachers who were not. hear nothing because the report had deafened him tem- sufficiently trained-a condition that prevails at least porarily."ls in Germany. This fact compels the requirement (unOne of the worst explosions on record was the disas- fortunately not yet fully appreciated) that chemical inter a t Oppau near Ludwigshafen on May 21, 1921. For struction be imparted only by persons who are thorsome unknown reason, 4500 hundred weight of ammo- oughly trained for this assignment, and that the young nium sulfate-nitrate exploded, 559 people were killed, people should be made acquainted with the most es2053 buildings damaged, of which 1036 were completely sential chemical facts. demolished. It had been the usual practice to break up The domain of possible chemical accidents is trethe solid masses of the salt by blasting, a procedure con- mendous, and only a few of these could be mentioned sidered perfectly safe after numerous trials had never here. To avoid such unfortunate events it is not caused the material to detonate. Perhaps, in some strange manner, the salts had become segregated during NH,CI
+ KNO1
KC1
+ N, + 2H.O
" Z. angew. C h m i e , 40,809 (1927).
Chem. Ztg., 66,321,415 (1942). Chem. Ztg., 66,314 (1942) describes a method of &voidingerplosions of ether due to peroxides. l7
Is
Z . nngeur. C h n i e , 33 (2), 245 (1920). Ber., 27,2764 (1894).
la
,
DECEMBER. 1950
enough to rely on official regulations and directions; the primary factor is that the operator must do the proper thing. The possibility of accident is determined not solely by materials and apparatus but pre-
673
dominantly by the actions of the person who uses them. Therefore the danger must be fought on the psychological front; people must be properly enlightened, instructed, and above all trained to be careful.
