June, 1925
INDUSTRIAL A N D ENGINEERING CHEMISTRY
555
The Hazard of Carbon Monoxide to the Public and to Industry"' By S. H. Katz PIT'CSBURGH
EXPERIMENT STATION, BUREAUOF MINES,PITTSBURGH,
PA.
Carbon monoxide is likely to exist anywhere; it is insidious and asphyxial in character. For this reason it has been the subject of many studies in the fields of hygiene, medicine, chemistry, and engineering. Proper regulation of gas stove burners will reduce the amount of carbon monoxide formed. Small amounts of this gas in the air can be detected by a simple color test. Two new devices have been developed for the protection of persons who are obliged to work in the presence of carbon monoxide, one a n oxygen breathing ap-
paratus, and the other a gas mask t h a t is effective against all poisonous gases, vapors, and smokes. Other results of recent research on carbon monoxide include a treatment for resuscitating persons overcome by this gas, and the development of a simple test for determining carbon monoxide asphyxiation. New problems in ventilation engineering have resulted frpm the increased use of the automobile. The solution of the carbon monoxide problem in the Holland tunnels between New York and Jersey City and the Liberty tunnels near Pittsburgh, Pa., is described.
HEMISTS and engineers understand the chemical reactions which yield carbon monoxide, including the incomplete combustion of carbonaceous materials in a restricted supply of oxygen. They realize the presence of carbon monoxide in blue water gas, coal gas, producer gas, blast-furnace gas, and many flue gases from stoves3 and furnaces, and they know it exists in mines after explosions and during and after fires. They are informed that carbon monoxide is poisonous because it combines with the hemoglobin of the blood to the exclusion of the oxygen needed to support life. However, they may not fully realize that carbon monoxide is prevalent in the atmosphere of many industries, in the air of garages, and even in city streets due to motor exhaust, and actually in homes having imperfect flueless stoves. The fact is that large numbers of the populntion breathe small amounts of carbon monoxide almost daily. A very small amount (1 part per 10,000 parts of air, or 0.01 per cent) endured 3 to 6 hours per day for about a year and a half has no noticeable consequencesJ4but larger amounts (4parts in 10,000 for exposures exceeding one hour or greater concent'rations for shorter periods6) may cause
sickness, unconsciousness, or even death. Much of the recent advance in knowledge and technic of carbon monoxide has been brought about by considerations of protection of persons and h j g'iene. Thus, the presence today of carbon monoxide in the air breathed by so many persons, and the likelihood of encountering dangerous concentrations under accidental circumstances, occasioned numerous studies of hygiene, medicine, chemistry, and engineering relating to carbon monoxide. Research staffs of sereral federal bureaus, various state departments of labor and industry and of public health, municipal engineering and health boards of larger cities, and some colleges are devoting considerable effort to the solution of various problems connected with this gas. It receives the attention of the safety organizations of many branches of industry; municipal gas-distributing companies have considered numerous questions relating to it. Undoubtedly, more is published for public attention about carbon monoxide than about any other gas. Some recent developments pertaining to carbon monoxide are described in this article.
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Received March 12, 1923. Presented before t h e Section of Gas a n d Fuel Chemistry a t t h e 69th Meeting of the American Chemical Society, Baltimore, hId., April 6 t o 10, 1925. 2 Published b y permission of the Director, U. S. Bureau of hlines. Jones, Berger, and Holbrook, Bur. M i n e s , T e c h . P a p e r 337; Jones a n d Yant, Bur. Itlines, Repls. of I n wsiigations, Serial No. 2572 (1924); Jones, Yant, a n d Berger, BUY. Mines, Rrpls. 0.f Investigations. Serial No. 2443 (1923); Jones and Yant, J . A m . Soc. Heat. V e n t . Eng., 29, 669 (1923). 4 Sayers and Yant, unpublished report, Bureau of Mines. 8 Henderson, Haggard, Teague, Prince, a n d Wunderlich, J . I n d . Hy. gicne, 8, 72, 137 (1921); report N e w York S t a t e Bridge a n d Tunnel Commission, 1921, p. 141; Sayers, Meriwether, a n d Y a n t , Public Health Rcports, May 12, 1922, p. 1127.
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Carbon Monoxide from Natural Gas Stoves The number of deaths recounted in newspapers which a r e a t t r i b u t e d to carbon monoxide from gas stoves is appalling. The serious proportions of this hazard seem only to have been appraised in recent winters. Tests by Jones, Berger, and Holbrooke on five common types of gas stoves burning natural gas w i t h o u t flue connections showed that dangerous concentrations of carbon monoxide were generated in unv e n t i l a t e d rooms through misadjustment of the stoves
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Figure 1-"Hoolamite"
Instrument for Quickly Determining Carbon Monoxide
E x t r a supply of carbon and tubes of hoolamite shown in case
8 Bur. Mines, Tech. Paper 337 (1923).
inaiirly througli burning excess gas. Two popular types shoved characteristics as follows: ( I ) Tiic S ~ U Y Cburning with yellow j e t s of flanic from lava tip hurncrs, holes 2.5 mm. (0.1 inch) diameter, evolved 1x0 carbon monorirb in an unventilated room when the flames exlcnded 10 cm. (-1 inchFs) or less and did not impinge upon any mctal surface, even if burned until the flame xias estinglrished for want of oxygen. If through misplacernmt of the burner the flames impinged upon a metal surface, dangerous amounts of carbon monoxide were liberated. ( 2 ) The radiaiit type of stove with non~luminousflame buming in ownwork earthen tubes evolved no carbon monoxide in an unventilated room when the radiants dowed not over onefourth or their entire length. When the glow extcnded through the entire radiants carbon monoxide was gcnerated when the oxygen in the room was decreased to I 9 per cent or less.
A safe rule is never to burn natural gas heaters in rooms in which persons sleep, unless t,he heaters me conneetod to flues or the windows are open. AIt.liough similar tests were not nmdo with manufnctnrecl gas, this rule is undoubtedly a snfc: one to follow, and it, applies to gas st,oves of every i.ype. Detection of Carbon Monoxide
A simple color test for carbon monoxide in air ’iyas rcccnt.ly Figure 2--McCaa Oxygen developed which permits estiAppZWaf Us inat.ion in less than 1 minute of concentrations from about 0.1 t,o 1.0 per cent by comparing the shade of color with permanent standard colors.7 Figure 1 shows the instrument. The active material is called “Hoolamite,” from the names of the i and A. X. Lamb, and consists of gra pregnated with a mixture of iodine sulfuric acid. IIoolamite is sealed in small glass tuhes, which are broken a t the t.ips for tat.. These are inserted in the main instrumcnt~,which consists of a tube of activated charcoal, through which the gases are d r a m , and a rubber hand hulb. The charcoal removes ail gases from the air stream which could cause a reaction similar to carbon monoxide and give a false test. The rubber hiilb discharges through the IIoolainitc, changing it from light gray to blue or green owing to liberation of iodine hy the oxidation of carbon monoxide when the latter gas is present. A color scale wit,h figures carresponding i o the respectjive percentages of carbon monoxide is fixed alongside the tube of Iloolamite. Carhon monoxide indicators are usually carried by minerescue creivs when entering a mine aft,er an accident, a used in many other situations. No knowledge of che is required, so that anyone can make the tests. Respiratory Protection from Carbon Monoxide Carhon monoxide should he avoided so far a.s pos ‘ t,he duties of some persons require them to work i pheres containing some of the g:is-for instance, cit. miners and engineers who must fight fire in mines entombed men after a mine explosion, and s around blast furnaces. Considerable progress has been made 7 Hoover, “XIS JOURNAL. 13, 770 (1021). Lamb and Noaver, U. S Patent 1,321,082 (November. 1918), Kafz and BlarmGeld, Tnrs J O U P N ~ L ~ 14, 304 (1922).
in recent years in methods aiid technic of respiratory pr0it.ction against carbon monoxide. OXYOEX XREAl’BlNG ~PPAR,\Tns-Self-~~illtaiired OXygell breathing apparatus have heen used for about sixteen years in mines of the United States for protection from rarhon monoxide during fires or following explosions. Such appa.ratus enable men to penetrate atmospheres containing insufficient oxygen to support life, such as mines, tanks, flues, or chemical apparatus, or unbrcathable atmospheres due to presence of any noxious gases which a man’s skin can withstand. Figure 2 pictures a McCaa 2-hour apparatus8 rccently developed in the Bureau of Mines. Its essential features are a supply of highly compressed oxygen in a steel cylinder; a breathing hag which receives the oxygen from the cylinder and holds it at approximatelyatmosphericpressurefor breathing; a circulatory breathing system of ( a ) flexible rubber tubes and valres which lead oxygen to the mouth for inhalation, and condu& the exhalations through ( h ) an alkaline absorbent to extract, the carbon dioxide and then return the residual oxygen to the (c) breathing hag. An automatic reduring valve supplies oxygen from the higli-pressure eyliiiders a t the rate it is consumetl. The McCaa apparatus is t,he light,est for its t.ime of service of any oxygen breathing apparatus, the weight being 30 pounds. CAItBON k~oNoXlnEG A S MASKS--The arllly gas tnask developed during t.he World War protected against the various miIit,ary gascs, hut .slien transferred to industry it had twi iinportiint deficiencies: i t afforded no prot,ect,ion again*t, carbon monoxide, and practically none against itminonia gas. To meot these deficiencies the Bureau of Mincs undert,ook to develop a mask effective against all poisonous gases, vapors, and smokes, whielr re] Universal gas inask sulted i ~ the (Figure 3).9 The canister contains the following dry, granular absorbents arramed in order from bottom to top: (1) Activated charcoal, for restraiiiiiig organic vapors. (2) Caustic pumice (caustic soda on pumice s t o x ) , for acid gases. (3)Fuscd calcium chloride, for removingwatervapor. (Water v ~ p o r , if dlowed to penetrate, prevents the action of the next material which is a catalyst.) (4) EIopcaliie, a specially prepared mixture of copper and manganesc oxides, for destroying carbon monoxide. (I-Iopcalitc catalyzes thc reaction ZCO 0 2 = ZCO1, causing F i ~ u r e3-ACarbon M o n it to proceed a t ordinary temperaoxide Gas Mask tures.) (5) Silica gel for removing ammonia. (0) Filters of cotton wool to remove suspensoids, such as smoke,
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as mask does not. supply oxygen, hence it does not protect against at,mospheres deficient in oxygen. illst 1 or 2 per cent of asphyxial gases s otherwise normal or contai a flame in a flame safety lamp. iversai type are now used hy ci mine-rescue crews, safety departments, and by small respirator called the “Self-rescuer,” designed to protect from ca.rhon monoxide for at least one-half hour, wa.s recently developed by the Mine Safety Applianees and Bloomfield. Bur. Miner, Tech. PoDcr 34s (19241. Kats, Bloomfield, snd Fieldoer. Ibrd ,900 (1923)
IKatz I)
I N D USTEIAL A N D ENGINEERING CIIEMISTR Y
dune, 1025
Company aud is officially approved by the Bureau of Mines.'O The Self-rescuer may be carried on a miner's lielt or in his coat pocket. I n case of fire or explosion it protects against carbon monoxide long enough to enable escape from the mine or to barricade against the deadly gases. Ilundreds of lives will undoubtedly be saved by Self-rescuers in years to come. Resuscitation
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ture of pyrogallic and tannic acids. A colored precipitate fontis, wlrich varies from brownish gray t,o deep pink, depending upon the amount of carbon monoxide-hemoglobin present. Comparison with a set of permanent standard colors identifies carbon monoxide, and determines the percentage saturation of the blood. This blood color test is also used to determine srnaU proportions of carbon monoxide in air. Ventilation Engineering
Persons overcome by carbon monoxide suffer from want of oxygen, and in this respect the case is similar io that of a Carbon monoxide evolved in the exhaust from automobiles drowning man. Treatment for carbon monoxide asphyxia- 1x1s given rise to new problems in ventilation engineering. tion requires the presence of pure air or a supply of oxygen, Abont 2% cnbic meters (10,000 cubic feet) of pure air per warmth, absolute rest (the patient should he carried) and, if minute 1nay be required to dilute the exhaust from an automobile to entirely harmless breathing is stopped or is proportions; this amount of shallow, artificial respiration dilution may be decreased, Iiy the Schaeffer prone presliowever, as the time of exsure method" should be adposure of persons to the gas ministered immediat,ely, and continued until the pabient mixture is reduced. Large b r e a t h e s naturally. The garages where many automobiles come and go, as well as oxygen, if a t hand, shonld be factories, thus have a probgiven, for it helps t,o siist.ain lem in the carbon monoxide the patietit and accelerates which affects the w ~ r k e r ; ' ~ liy mass action t:br elirnination of carbon monoxide from and provision must s o m e times be made for removing tlic blood. the gas by special ventilath receiit modificat,ion in t r e a t m e n t , dt:vt.lopad by ing systems. The greatest p r o b l e m s , lienderson and Ilitgggard, has however, are those of ventilieen the administration of a lating the Holland tunnels 9 5 5 oxygen-carbon dioxid f
