The American Carbon Manual/Physiological Effects of Chromic Salts


It is important to those using chromic salts to have some knowledge of their effects on the health if used carelessly. The bichromates taken internally are active poisons, but Dr. Alfred Taylor remarks in his work on poisons, that notwithstanding their extensive use in the arts, well-observed instances of poisoning by means of a bichromate are rare. Dr. Cloet, who made a careful investigation into the condition of health of the people engaged in a bichromate manufactory, states that, taken internally, it is not poisonous in such minute doses as cyanide of potassium, about fifteen grains being necessary to cause death in a healthy adult person; but it is in coming in contact with the mucous membrane, or with a slight abrasion of the skin, that its most injurious action is found,—obstinate and dangerous ulcerations, issuing occasionally in complete destruction of the part, ensuing. It is observed that when used with care, no danger whatever need be apprehended, as it is quite innocuous on the skin when there is no abrasion; no absorption of the poison taking place, except by the mucous membrane, or through a wound of some kind. The important point for photographers to observe is, to avoid contact with the bichromate where there is any scratch or lesion of the skin, and to avoid contact with the eyes or nostrils with fingers which have recently touched the chromic salt. Dr. Cloet says:

“This salt (bichromate of potash) in small doses, say a few grains, acts as a purgative; if in larger doses, say fifteen grains, it acts as a poison. A workman in a factory put some bichromate into a barrel of cider, by way of joke. The cider was rendered dark in color, but still the other workmen drank of it, and were all affected with severe colic and diarrhœa. Disease of the nostril has been produced by workmen who, having stained their fingers with the salt, have put them into the nostril.

“In transforming neutral chromate of potassa into bichromate, by means of acid, the vapor arising carries with it an infinity of pulverulent molecules of the product, which spread through the workshop. This cloud of particles is easily visible in a ray of sunlight. The molecules inspired give a bitter and very disagreeable taste to the palate; but as profuse salivation is the result, the chromate is thrown off in the saliva, and has not time to inflict any permanent injury. If, however, respiration be made through the nose, the molecules are dissolved in the layer of secretion which lies on the membrane, creating a violent pricking, suffusion of tears, and irresistible sneezing. In time, the membrane begins to be thrown off, and portions of it are carried into the handkerchief used in blowing the nose; this process, when once started, goes on so rapidly, that after a period of six or eight days the septum becomes thin, permeated with openings, and is ultimately detached altogether. Snuff-takers escape this evil.

"On the skin, in its normal state, and intact, the bichromate exercises no baleful influence; the hand may, in fact, be plunged into a hot concentrated solution of the salt, without fear; the hand may also be covered with the salt for an entire day without any observed effect; but if the skin is torn or abraded, however triflingly, by the prick of a pin for example, a sharp pain is felt on contact of the salt, and if it be left in contact with the wound, the caustic character of the salt is brought out intensely, the cutaneous tissue is decomposed, and violent inflammation is established. These symptoms are accompanied with intense pain, especially in winter, when the cold is severe; the action of the salt does not cease until the cauterization has penetrated to the bone.

"When the skin is abraded, and the bichromate has produced ulceration, the best treatment is to wash the part thoroughly with a feebly alkaline water; then, if inflammatory action follows, to poultice, and afterwards freely apply subacetate of lead in solution."

Dr. Taylor recommends for cases where the poison has been taken internally, emetics and carbonate of magnesia or chalk, mixed with water into the consistency of cream.