Chromium Salts Safety Precautions for Chemical Plant Operatives C. H . S . T u p h o l m e R u n c t o n C o t t a g e , Lower B o u r n e , F a r a h a m , Surrey, E n g l a n d
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N VIEW of the increasing use of chromium compounds in industry and the fact that their effect on the skin of operatives has been the subject of much discussion lately in Britain and on the Continent, an investigation by a French committee on this topic is of some interest. The results of the investigation are reported at great length in Tiba. In this, the investigators point out that apart from chromes as a base, the chemical industry prepares compounds of chromic acid, or to be more precise, chromic a n hydride, CrOs. The effects of this a n hydride in water solutions are complex: the corrosive effect of acid, the oxidizing effect, its own particular effect. T h e acidity, especially where the acid is concentrated, produces burns. The very powerful oxidizing action rapidly destroys the membranes and cells. The peculiar effect of the anhydrides is that they provoke acute dermatitis (chrome eczema). The greater the concentration of t h e acid, the greater is the combined effect. 1 Chromic acid is now in constant use in electrolytic deposition of chromium and in the tanning industry. It is an auxiliary product, at least, in dyeing. The alkaline bichromates of sodium, Na*Cr207, and of potassium, K2Cr207, serve as a base for other salts of chromium and for diverse pigments, and are used in bleaching fatty bodies, in tanning, as mordants in dyeing, as oxidants, etc. The soda salt is the cheaper and is the more used. Although these alkaline salts have not the corrosive effect of the acid, they are capable of destroying membrane and cells. They constitute a danger, therefore, for the mucous organs, provoking ulcers, and for the skin on which they form a painful rash. Consequently, their use necessitates precautions—the wearing of rubber gloves, ventilation of the work rooms, thorough cleanliness on leaving work, a n d great care in manipulations. This also applies to sodium chromate and potassium chromate, which are used in several chemical preparations, in dyeing, and in softening boiler water. It is curious that the combination of potash and chromic acid is used medicinally; it is the Kale bichromicum of the French pharmacopeia. (Potass bichromas of the B. P. expressed as K 2 Cr0 4 , Cr0 3 ). It is useful in bronchitis, pulmonary catarrh, and even for simple colds. Among the other salts of chromium most used in the chemical industry may be cited: sulfate of chromium in mordanting, tanning, and chroming; acetate of chromium in dyeing; chloride, fluoride, and formate of chromium in dyeing and tanning; and chrome alum in dyeing. These compounds are equally capable of causing dermatitis, and trken internally are definitely poisonous. Pigments based on chromium are in varied use in the coloring industries a s paints and lakes, and for coloring paper, molded articles, and rubber. They are almost always toxic. The pigments based on lead and chromium are especially dangerous. Among these are chrome yellows, which are compounds of lead and chromic acid, chromates of zinc and barium, 1
In a very diluted form the solution can be usefully employed to allay the pain of the bites or stings of insects and reptiles. On moistening the wound with a little dilute chromic acid, the cure is remarkably rapid.
which are light yellow colors used in interior decoration, chromates of mercury (orange yellow, reds, and violets), chrome greens, formed by a mixture of Prussian blue and chrome yellow (a very violent poison), oxide of chrome green based on chromic anhydride, zinc green, formed by a mixture of chromate of zinc and Prussian blue, and red lead, which is a basic chromate of lead and is very poisonous. These pigments have valuable and remarkable properties from the point of view of color. They have beauty, capacity, and covering power and are still much In use. If a substitute replace? them it is rather because they are expensive than on account of their toxicity. Nevertheless, precautions should be taken in employing them. There is considerable difference in opinion as to the use of salt** of chromium. Take, as an example, the employment of chromates in the refrigerating solutions intended to exert an antirust action on iron and steel recipients. Some writers condemn this practice. Another writer has expressed the contrary opinion, with many arguments. He states that the quantity of chromium used is very small and that its toxic action is limited to that of the initial dose and independent of the small additions in the course of usage. He also argues that the chromates formed diminish the activity of the chromium and that the concentration of the solutions is t o o weak to be dangerous. T h e investigators are not of his opinion and deprecate the making light of possible dangers. The chromic oxidation of alcohols is another dangerous practice which has become general. The investigators emphasize the dangers of chromic acid, which is corrosive, oxidizing, and poisonous. The salts are variously active, but as a general rule the derivatives of chromium, by reason o n the one hand of their importance and o n the other of the accidents they have already occasioned, must be classified as dangerous. In Germany chromium took t h e second place in the record of chemical accidents in t h e years 1918, 1920, 1924, 1925, and 1926. In France t h e regulations relate to lead, mercury, and the radioactive metals and there is no mention of chromium. The salts (fluoride, phosphate, sulfate, formate, and chrome alum; are in principle less dangerous than the salts of chromic acid (chromates and bichromates), and should be used when the choice is possible. T h e chromates act b y transformation into bichromates and the effect of the chromic acid is therefore the same in the two forms. T o sum up, the risks of the employment of chromic acid, salts of chromic acid, and salts of chromium, in decreasing order are: dermatitis, destruction of the membrane and cells producing ulcers; burns, perforation of the nasal diaphragm; internal ulcerations; attack on the respiratory mucous organs; intestinal troubles and rapid aggravation of small wounds and scratches. Precautions t o be taken are: (a) Individuals with a tender or inflamed skin should not work with chromium compounds unless they are thoroughly protected. This especially applies to those with chromic
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inflammation externally or internally a n d t o workers with scratched h a n d s or small body wounds. (b) Thorough cleanliness should be prescribed a n d t h e hands frequently washed. B o t h h a n d s and face should b e washed before leaving t h e works. Bisulfite of sodium should be provided a n d used in t h e lavatories. (c) T h e wearing of rubber gloves m u s t b e obligatory. (d) T h e workers should be informed a s t o the dangers in order t h a t t h e y m a y guard against them intelligently. (e) Cover the vats a n d m a i n t a i n good ventilation t o carry away t h e chromic fumes.
Chromium compounds are valuable and of absolute and irreplaceable necessity, and with these precautions their employment is reasonably safe. Shortage of Skilled Workers i n German Chemical Industry ERMAN production of chemicals and allied products continued to surge ahead during the first half of the current year, with the demand for certain lines so heavy at times that factories found it difficult t o make prompt deliveries, a c cording to a report made public by t h e Commerce Department's Chemical Division. Measured by man hours performed, a new record was established and some plants reported a shortage of skilled workers, as well as the need for more trained professional and scientific personnel including chemists and engineers. This development was reflected in the lengthening of the average working day t o 7.98 hours in May of this year from 7.77 hours in May, 1936. Expansion in the production of t h e newer synthetic substitute materials, in line with the national self-sufficiency olicy, resulted in heavy demand for such asic materials as acids, alkalies, cellulose, and coal-tar derivatives and the shortage in some lines resulted in closer official control over such products as phenols, lead, and copper sulfate. Insufficient supplies of imported technical oils and fats, lead, and other pigments caused some inconvenience in the soap, paint, linoleum, and other consuming branches. While export trade contributed in some measure to the expanded chemical output during the first half of the year the results were due chiefly to the marked upswing in domestic demand for substitute materials of chemical origin.
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ECENT decrees of t h e Italian Government provide for assistance t o synR thetic rubber manufacturers in the form of reduced duties on machinery and raw materials, lower taxes, and production subsidies, Rome reports state. President Weidlein has appointed FRANK C. WHITMORE the representative of the AMERICAN CHEMICAL SOCIETY on the
occasion of the celebration of the one hundred and fiftieth anniversary of the founding of Franklin and Marshall College, t o be held o n the campus, Lancaster, Pa., October 14 to 17,1937.
