VOL.4, No. 5
POISON HYDROGEN Su~prnsAS AN INDUSTRUL
613
HYDROGEN SULFIDE AS A LABORATORY AND INDUSTRIAL POISON* W. P. YANT, SUPERVI~ING CR&MST,HEAL- LABORATORY SECTION, PIMSBUROH EXPERIMENTAL STATION,AND R . R. SAYERS,CHIEFSURGEON, BUREAUOX MINES
The odor of hydrogen sulfide characterizes the thoughts most chemists have of their course in qualitative analysis. This odor was regarded as being a concomitant of the air of that particular laboratory. Though the textbook may have stated that hydrogen sulfide possessed poisonous properties it was seldom thought of in that light. This was in a large measure due to the fact that it was given no emphasis in the lecture room which of course signified it was not a potential question for quiz or examination, and hence was a matter to be forgotten in passing. But when the subject of hydrocyanic acid was introduced the poisonous properties were elaborated upon until the student would wonder how anyone lived to describe its odor. The very shape of the symbol HCN was mentally transfigured into the conventional skull and cross bones. As a matter of fact, hydrogen sulfide and hydrogen cyanide may be classed in the same category of poisonous gases. Prom comparative data the dosage of hydrogen sulfide required to kill most animals in a very short time is even less than for hydrogen cyanide-namely, 0.10 to 0.20,'p2 and 0.302 per cent in air, respectively. On the other hand, the amount causing ill-effects from long exposure to low concentrations appears to be less for hydrogen cyanide. However, in either case the diierence is not significant from the standpoint of health and safety. The fact that the poisonous properties of hydrogen sulfide have been greatly under-estimated and not sufficientlyemphasized bas been reflected in the apparent existing indifference to the dangers from this gas and the slowness of chemists and doctors in recognizing it as a source of frequent cases of gas poisoning. In view of this it appears that a better understanding of its toxic effects should be given to students of chemistry, not only from the standpoint of avoiding unhealthy atmospheres in university laboratories where its dangers can be easily mitigated and controlled, but to bring the matter to the attention of the students so that they can properly evaluate the dangers from this gas when they become engaged in industries.
* Published with approval of the Director, Bureau of Mines, Department of Commerce. Sayers, R . R., and others, "Investigationsof Toxic Gases from Mexican and Other High Sulphur Petroleums and Products," Bureau of Mines Bull., 231,1925,108 pp. K. B. Lehman, "Tabelle der Kleinsten Mengen schiidlicher Fabrikgase, welche noch giftig sind uud der Mengen, welche allenfalls atragen werden" in Rudolf Robert's "Kompendium der praktischen Toxikologie zum Gebrauche fiir Aerzte," Studierende und Medizinalbeamte Stuttgart, 1912, p. 45.
Occurrence of Hydrogen Sulfide Hydrogen sulfide is not merely a laboratory reagent. It has wide occurrence in nature and in industrial processes, and from these sources i t has been a source of considerable trouble as an industrial health hazard. At present the most prevalent site of trouble from its natural occurrence is in the production and handling of certain types of high-sulfur crude oil. The hydrogen sulfide occurs as a constituent of the natural gas above the oil, or is dissolved in the crude petroleum. This is especially true in many Texas fields,s and also in Mexico and South America. As much as 8 to 10 per cent bas been found in the gas of one particular field where in several cases i t caused almost instantaneous death to men after only one or two breaths. In the petroleum industry the greatest trouble from hydrogen sulfide is irritation of the eyes and respiratory tract. These occur by the huudreds and are the cause of much inconvenience and delay. Entire crews are frequently incapacitated for several days and in one specific instance more than thirty men were rendered unconscious, and as many or more cases of irritation occurred before the well was closed in. The odor of sulfide is continuously present in these fields. The buildings or equipment which have been painted with white lead rapidly change in color to a brownish black. The silver money in use a t the camps is black from a coat of silver sulfide. Many dead b i d s and animals are found in the vicinity of the tanks and wells. In the handling, shipping, and refining of these high-sulfur oils there is the menace of hydrogen sulfide.' The oil coming from the well contains large quantities of hydrogen sulfidein solution part of which is given up during the process of pumping to flow tanks, thence to tankers, and finally to storage tanks a t the refineries. This escape of dissolved gas renders the vapors above the oil in all these containers exceedingly toxic. Danger from the dissolved gas or from hydrogen sulfide generated during heating persists throughout many stages of the refining process and numerous deaths and hundreds of cases of severe irritation have been caused. In addition to this major natural source of trouble, hydrogen sulfide has been encountered in dangerous amounts, and has resulted in cases of poisoning in gypsum and sulfur mines and in the sinking of caissons and digging tunnels. To a lesser degree i t has also been found in gases coming from marshes, sewage and the decay of organic material, in coal mines, volcanic gases, and in the water from certain springs. Health hazards from hydrogen sulfide are also prevalent in various industries. These occur not only in those where it is used as a chemical W. P. Yant and H. C. Fowler, "Hydrogen Sulphide Poisoning in the Texas Panhandle, Big Lake, Texas, and McCamey, Texas, Oil Fields," Bureau of Mines Reports of Investigations, Serial No. 2776, Oct. 1926. 20 pp.
reagent but in others where it is liberated in the process. As specific examples may be cited the manufacturing of chemicals, the manufacture of gas, in coal mining from the products of combustion of black blasting powder, in metal mining from the blasting of certain types of sulfide ores with dynamite, and in the refining of petroleum to which reference has been made. Types of Poisoning and Occurrence of Symptoms The possibility of poisoning is present wherever hydrogen sulfide exists. A study of the accidents caused by hydrogen sulfide gas shows that the cases may be readily divided into two distinct types-namely, (1) acute, or asphyxiation; and (2) subacute, or irritation, resulting usually in conjunctivitis (inflammation of eyes), and inflammation of the respiratory tract, such as pharyngitis (inflammation of the throat), bronchitis (inflammation of the lungs), and pneumonia. These types may be described briefly as follows: Acute.-A study of the cases of acute poisoning shows that i t results in almost immediate unconsciousness, followed by death if rescue is not quickly effected and treatment given. In cases where rescue and treatment can be quickly accomplished the victim usually regains consciousness almost immediately. Headache and nausea may exist for several hours after but in most cases they are able to return to work feeling almost normal in the course of two to three hours, or a t least in a day or two. Typical cases of acute hydrogen-sulfide poisoning are as follows: 1. A student who had been generating hydrogen sulfide carelessly opened the hoods which contained the gas and breathed some of i t for a period of possibly one minute. He fell unconscious t o the floor, and his fellow students carried him t a fresh air. No treatment was given and he was unconscious for only a few minutes. After regaining consciousness he went home, but returned to college the second day following. No after-effects were noted. 2. A gauger who opened the hatch of a n oil tank for the purpose of measuring the quantity of oil was found dead on the ground below. 3. An oil-well driller and his helper unexpectedly drilled into the gas and were both found dead on the derrick floor. 4. A chemist engaged in the manufacture of cadmium sulfide opened the lid of the reaction tub. He fell unconscious from hydrogen sulfide poisoning before he could replace the cover but by falling into a zone of fresh air be recovered in a few minutes.
Subacute.-In subacute cases, symptoms of irritation of the eyes and respiratory tract are found. The degree of poisoning varies with the concentration of the gas present and the length of exposure. Typical subacute cases of hydrogen-sulfide poisoning are as follows: 1. A laborer worked all night in a n atmosphere containing a small amount of hydrogen sulfide. He complained that his eyes pained. The following day his cornea was lusterless and exceedingly painful. Marked lacrimation (tears in eyes) and photo-
phobia (pain on exposure to light) existed. Following this the exposed portion of the cornea became doudy, and later peeled. For several days the patient was unable to use his eyes, but a t the end of a week the conjunctivitis cleared up and his eyes were not permanently damaged. He was able to return to work after ten days' treatment. 2. A drilling a e w and connection a e w were engaged in dosing in an oil well from which natural gas containing a relatively small amount of hydrogen sulfide was escaping. Although the concentrations were not sufficient to cause acute cases of poisoning, nearly all the crew were affected by eye irritation with the result that the work was suspended far several days. The symptoms in these cases were, exceedingly great pain and a feeling of sand in the eyes, inflamed conjunctiva even to the extent of bulging, photophobia, and temporary blindness. A few felt a choking sensation and fullness of the lungs.
The occurrence and type of symptoms resulting from exposure to varying concentrations of hydrogen sulfide are shown in the table on the opposite page which has been compiled from various sources of data on men and supplemented in the higher percentages by data from investigations on animals. Reference to loss of sense of smell will be noted in this table. This refers to the inability to detect the characteristic odor of hydrogen sulfide after a few minutes' exposure, and plainly shows that the sense of smell cannot be used as a reliable means for detecting dangerous concentrations. This phenomenon is noticed with practically all gases and vapors which have a strong characteristic odor. If the gas accumulated slowly i t is very possible that dangerous concentrations would occur before one who was continuously exposed would detect it as a strong concentration. This explains the description given by many victims of poisoning, that they did not smell hydrogen sulfide but that unconsciousness was produced quickly and pleasantly. Treatment Conjunctivitis.-Consultation with physicians in oil-fields who have been treating these cases advise that the following treatment for conjunctivitis has given excellent results-not a single case failed to respond to treatment where the patient has done his part by following instructions: 1. Relieve pain by drops of butyn, or hutyn and epinephryn, or holocain in severe cases in which the pain is not relieved by the former. 2. Follow with campho-borate. One doctor varies this practice by using boric acid ointment. 3. Drops of colloidal silver iodide (neo-silvol), or argyrol (5 to 10 per cent). 4. Throughout the treatment use hot compresses alternating with a cold compress if pain is too great.
Rhinitis, Laryngitis, and Bronchitis.-Irritations
of the nose, throat,
VOL.
4, NO. 5
617
HYDROGEN SULFIDE AS AN INDUSTRIAL POISON TABLE 1
TOXICITY OF HIS ON MEN (COMPILEDFROM THE WORKOF LEHMAN AND THE WRITERSOF B U ~ AOF U MINES BULLETIN 231)' H2S percent
I/#
to
2 minutes
2 to 1.5 minutes
15 to 30 minutes
30 minutes t o 1hour
Coughing; irrita- Disturbed respira- Throat irritations tion to eyer; loss tion; pain in of sense of smell eves: . . s1eeoiness . Loss of sense of Trachea and eye Eye and trachea smell irritation irritation Irritation of eyes; Irritation of eyes loor of sense of smell
,050 .060
080 -070
~ i s c u ~ respirat x-e-edirritation irritation to tion; to eyes and nasal loso 01 sense 01 irritation 01 eyer *act; dull pain smell in head; weariness:. lieht shv ~ ~ die Serious ~ e m Lrita~ Severe i pain in eyes ~
coughing; andunconscious. ned
collapse ~
~
turbanecJ;irrita. tiontoeyes;diffi. culty of respira. tion: eo~lapse'
,070 .080
COIIS~JC
UnconsciournesrD
,080
ca~lapw Uneooseiousnerra
Collapse unconsciourness deathm
.lo
Collapse Unconsciousness"
Collapse Unconsciousness death'
.15
Data secured by the p~
tion; light shy; palpitation of heart; few cares of death'
Collapse unconseiournese deathn ~ ColbPe ~neonseiourness death"
.lo
Painfulseeretionof tears; wearinens
from experiments on dogs, which,
~
1 to 4 hours
'
4 to 8 hours
salivatianand mu- herrased r y m p cou. di.charg.; toms* share main in ~eyes; coughing Difficultbreathing; indirtinct vision; S e r i o u s irritating light shy effects Light shy; nasal catarrh; pain in Hemorrhage and eyes; difficult death' breathing; pain in head iojeetion of eanjunetiva D ~ Z Z ~ ~ weak~SS; X I . . . increased ; .ign3 01 k i t a and death*
.~
~
t
~
8 to 48 hovrr Hemorrhage and death'
Hemorrhage and death"
~
~
and head dirriness; trembling of extremities: great weakness and death'
~
~
~
i
~
t o lehman in Arch. Hyg., 14, 135-89 (1892). have a susceptibility similar to men.
~
and lungs are treated symptomatically. One doctor has had good success in the use of "anespray" for the throat. Treatment for Subacute Poisoning All of these treatments should be under the supervision of a competent physician. While the symptoms may appear trifling, they should receive medical attention a t once because of the complications which often arise. The application of hot and cold compresses in themselves will relieve pain in cases of conjunctivitis, and irrigation with boric acid will he helpful in slight attacks, but only sterile compresses and eye cups should he used. The difficulty of self-diagnosis as to the severity of the.attack, makes "home remedies" and "home treatment" inadvisable. If a man had a natural tendency toward eye or respiratory weakness, his exposure to hydrogen sulfide gas might result in a complicated condition which would prolong the recovery period. This makes it especially imperative that all cases should be treated by a competent physician. It has been reported that solutions containing cocaine have been prescribed to be used as an eye wash in cases of "gas eyes," the name applied to conjunctivitis caused by H2S. This is a very dangerous practice because the pain is relieved temporarily, and men will go into the hydrogen sulfide gas repeatedly when they should be receiving proper care. These repeated exposures to H2S and use of such eye washes often result in corneal ulcers and in permanent injury to the patient's eyes. Treatment of Acute Poisoning In many cases of acute hydrogen sulfide poisoning there is an immediate cessation of respiration. Thus any treatment to be effective must he given immediately and be so simple that it can be given by fellow workmen. There is not time for summoning aid before beginning to resuscitate the victim. I n view of this the following treatment is outlined: 1. Get the patient into fresh air. 2. Give artificial respiration by the Schaefer or prone method,& if breathing has ceased, become markedly labored, or impaired. 3. Summon a doctor.
If breathing has ceased or ceases during treatment, artificial respiration should be continued until breathing resumes, or a t least for a period of three hours, unless the patient is pronounced dead by a doctor.
A Hint to Laboratory Workers In concluding the reading, many teachers of chemistry will no doubt "Manual of First-Aid Instruction for Miners." by a Committee of Surgeons on Standardization of First-Aid. Revised hy R. R Sayers, Bureau of Mines, 1921, pp.
33-5.
VOL. 4, No. 5
HYDROGEN Sularo&as AN IND~STRUL POISON
619
wonder how they have escaped being poisoned by this laboratory commodity. A few may even be inclined to be skeptical. However, if they are reminiscent a considerable number will recall cases where students became unconscious from breathing hydrogen sulfide. In most cases of acute poisoning recovery was very rapid and the incidents were explained, or thought of more in the terms of fainting, choking, or couldn't get his or her breath. No direct thought is given to the direct poisonous action of the hydrogen sulfide, and to the fact that death might have resulted in a few minutes if the victim had breathed the gas a few seconds longer. Fortunately, in most chemical laboratories, hydrogen sulfide is generated in relatively small amounts and in most cases the atmospheres capable of producing acute poisoning exist only around the generator. When a student breathes concentrations high enough to make him unconscious he falls down or away from the poisonous atmosphere. In addition to these acute cases it is believed that many more cases of irritation of the eyes and respiratory tract occur among the students. These may have passed unnoticed or if observed a t all in the large majority of cases have been attributed to other causes.
