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SCF-ALLF-01788 I ... Other Volumes in this Series Users of this volume will find much value in its companion volumes. Here is the list: VoI.No. TITLE Stock No. 1 General Seniors am) Detailed Indci to ell Volumes......................................... 03237--I 2 Avietierc Aeronautical Indurtno Section 1 Air Transport Section................. 02127--2 3 Bane Steps in Accident Prevention........................................................................ 02277--3 4 Cement and Quarry Industries................................................................................ 02127*4 5 Qiantcal Industries ...................................................................................................02127--5 6 Coal Mining Industry................................................................................................ 02137--4 7 Construction Industry and Publie Employment (PublicEmployee Section)... 02237--7 8 Electrical Equipment Industry and Public Utilities................................... 02227--8 9 Farm Safety ............................................................................................................. 02127--9 10 Fertilizer Industry ..................................................................................................... 02227--10 11 Food, Meat Peeling & Leather Industries,Trades and Services...........................DZ277--11 12 Glass and Ceramics Industry and Rubber Industry........................................... 02277--12 13 Home Safety ............................................................................................................. 02277--13 14 Industrial Subject Sessions (Sponsored by ASSE|............................................. 02127--M 15 Labor ......................................................................................................................... 02277--IS 16 Maritime Industries (Marine Section).................................................................... 02277--16 17 Metals Industry ..................................................... 02277--17 IB Metals Products Industries (Automotive and Machine Shop Section Power Press and Forging Section).................................................................... 02277--IB 19 Mining Industry ....................................................................................................... 07277--19 20 Motor Transportation Industry (Commercial Vehicle Section)....................... 02277--20 21 Occupational Health Nursing Section....................................... ......................... 0Z277--21 22 Petroleum Industry ................................................... 02277--22 23 Printing and Publishing Industry............................................................................ 02277--23 24 Pulp and Paper Industry........................................................................................... 02277--24 25 Railroad industry ..................................................................................................... 02277--25 26 School and College Safety..................................................................................... 02277--26 27 Traffic Safely.............................................................................................................. 02277--27 26 Transit Industry ........................................................................................................... 02277--21 29 Wood Product! and Textile Industries................................................................ 02277--29 30 Early Morning Sessions, "Human Relations and Man*Management"............... 02277--30 1957 IURRENT SAFETY TOPICS Volume 5 r CHEMICAL INDUSTRIES PRICES OP EXTRA COPIES OP INDIVIDUAL VOLUMES VOLUME SIZE 12 or less pages-- 33 to 24 pages-- 25 to 48 pages-- 49 to 96 pages-- Over 96 pages-- 2 to9 copies Each $075 75 -45 .60 75 10to 99 copies Each $070 28 77 -30 75 100to999 copia Each $0.17 75 73 .45 70 Each $0.17 75 73 AS JO Complete set of Current Safety Topics (30 vol&.)--$950. Stock No. 022.17 All prices shown axe subject to a 10 per cent discount to National Safety Council members. Transaction* of the 45th Rational Safetg Congress (October 21*25,1957, Chicago, illJ NATIONAL SAFETY COUNCIL 425 NORTH MICHIGAN AVE. CHICAGO 11, ILL 220O2SBO2 mmto m . 022.27* 12 NATIONAL SAFETY COUNCIL 425 N. MICHIGAN AVENUE, CHICAGO 11, ILLINOIS ::A (=> i ft CONTENTS Safely m High Pressure Chemical Reactions...................................... W. R. Kinder 5 Controlling Health Hazards in a Chemical Plant...........Robert A. Kefooe, MJ). 9 Living in the Air We Breathe.................................................. ................H. H. Fawcett 11 Laboratory and Pilot Plant Safety {A Symposium) Laboratory Barricading of High Pressure and Extra Hazardous Reactions..........................................Godfrey J. Mol! 33 Flammable Materials--System for Rating..................... - - .William S. Wood 3B Toxic Chemicals.............................................................................. IL ^ Montello 42 A Bibliography of Toxic Chemicals............................................ ........................... *4 Waste Disposal........ ...................................................................Earl R. Wallace 52 Acids and Heavy Chemicals (Discussion Report). ........................R- L Allinson 54 Industrial Gaies Discussion Group.....................................................H#F. Reinhard 5fe LEARNING TO LIVE Learning to live--safely--was the drawing card which brought more than 13,000 men and women from the United States and 27 other countries to Chicago for the 43th National Safety Congress. These people gathered to exchange the latest ideas m safe attitudes, sate methods and safe equipment. Through speeches, panel discussions and symposiums, they acquired new ideas tor helping others--and themselves--to live, work, and play safely. This was the reason the Xational Safety Council was organized lt than half a century ago, a time when man's thoughts barely keot pace with the industrial revolution. Since then, man has introduced an atomic age which is bringing the continents closer and has made the earth a smaller world. And now* man anticipates inter-space travel! Through science and technology, man is progressing to increasing speeds in travel and production, and increasing dangers--new dangers never before encountered. These, in addition to the everyday hazards of life, occupied the thoughts of the safety people at the Congress. To encourage snore widespread knowledge of the various fields of safetv, the National Safety Council publishes the Current Safety Topics---30 volumes of condensations of Congress speeches and exchanges of ideas. Each volume is a handy reference to different phases of accident prevention. The complete set of volumes are listed on the back page of each volume. Since the proceedings have been edited and condensed for reference purposes, the complete original manuscripts with any charts or illustrations trsfri, are available in the National Safety Council files. Views expressed at the Congress or in any volume of Current Safety Topics are those of the Congress participants, and not necessarily those of the Xational Safety Council. THE CHEMICAL SECTION This volume is a record of the sessions held at the 1957 Xational Safety Conby ihe Chemical Section. The conduct of these Congress sessions each year is only one oi the many cooperative activities which the Chemical Sec tion carries on in behali of its members, and for the benefit of accident pre vention work in the chemical industry generally. The section gives guidance m the preparation of a great variety of technical and educational material useful in the day-to-day safety programs of chemical companies. The activities of the section are under the direction of its executive committee, the members of which are listed at the close of this volume. 3 1957 National Safety Congress mists, /times, dusts. Also asphyxia tion, irritation of lungs--acute (edema, pneumonitis), irritation of longs--chronic, pneumoconiosis, fi brosis, emphysema,' and granuloma (Be). In addition cancer of lung, deposition--radition within lung and hilar lymph nodes; specific carcino genic agents are hazards. Ingestion of chemicals, following upper-res piratory trapping of dusts, follow ing contamination of hands and handling things that go into mouth and following contamination of food stored in work rooms--oxen in dirty lunch rooms are potential dan gers. (2) nature of hazard--aspect of absorp tion--systemic effects such as: acute intoxication, percutaneous, respira tory, alimentary absorption (often two or all three combined); chronic intoxication--remote enzymatie or metabolic effects and organic dam age; or remote radiation effects fol lowing absorption and distribution of radioactive materials in body-- example--bone and marrow, follow ing absorption, distribution and me tabolism nf specific carcinogins-- example--bladder tumor. RECOGNITION AND IDENTIFICA TION OF HAZARDS 1. Toxicologic investigation (in labora tory) (stepwise with progress of re search and development in industry*) (a) screening--preliminary* choice or elimination of materials under con sideration-- --immediate toxicity--indicative of type of control measures based on portal of entry (type and point of application of preventive procedure) (degree of precision required in protection. L e. extent of apparent danger) (medio! criteria--type of antidpated-xnjury or disease) (b) Comprehensive--(adapted to the problems to be met) --manufacturing hazards --hazards of transportation and use as raw materials by others --hazards of consumer of final prod uct --cumulative effects if any 10 --metabolic fate is body--remote ef fects--long-term--chronic--injuri ous effects * --diagnostic and prognostic procedures based on results of investigation 2. Toxicologic investigation--{in plant) cliniol investigation of personnel --basis of all specifications for safe en vironment --sometimes the only baas for recognition of hazard, e. g. beryllium, occupational cancer CONTROL OF HAZARDS I. Medical measures of control--enviranTTwnnal--(operations, plant conditions and (how* men work) --clinical examination--all types. --policing the plant--(clinical findings and tests on personnel) --identification and quantitation of re sponses to observed exposure--within physiological (tolerable) limits--beyond physiological limits --warning of need for further protection --disposition of personnel with respect to exposure restriction of time (duration) of exposure--removal from exposure --temporary or permanent --personal protective equipment (choice and supervision, physiological criteria) adequacy of equipment employed--ade quacy of its maintenance--adequacy of its use --education, group meetings, written in structions, hygienic manual, combined w*hh operating manual --reports to engineering personnel (in both operations and industrial hygiene) and to management 2. Engineering measures of control --designing and applying measures of con trol--physical devices tor protection against chemicals--plant design--opera tions design--ventilating design --policing the plant (environmental moni toring) inspection critique of mainten ance operations--analysis of materials --air analyses. --personal protective equipment (choice and supervision--engineering criteria) --reports to medical personnel, and man agement (directly or through physician) 3. Administrative measures of control --appropriate organization of hygienic fa cility in relation to operations --appropriate budgetary provision for hy gienic effort Adequate control depends upon the com plete understanding of the hazard through physiologic and toxicologic research. In addition, satisfactory team work in cludes : Chemical Industries I. Physician (including nurse and techni cians) measures applied to personnel measures to be applied to environment (hygienic specifications) Z Engineer (including chemist, physicist and technicians) measures to be applied to environment (hygienic technologic applications) 3. Management proper organization proper financial implementation A LIVING IN THE AIR WE BREATHE by H. H. FAWCETT safety director, research laboratory, General Electric co., Schenectady, M. Y. Using m the air w*e breathe has been a problem since God created man from dust 2nd then breathed into him the breath of life! Bet even today, the vita] role of breathing in our daily life has not been com pletely appreciated. This paper reviews briefly (1) air contaminants, and (2) com mercially available respiratory protective de vices. with emphasis on their limitations, and on the training and maintenance necessary for safe and effective use. "day-by-day" thought and deliberate action to obtain. We live at the bottom of an ocean of air called the atmosphere, a name given to a mixture of several gases which consist mainly of four-fifths nitrogen and one-fifth oxygen. Virtually limitless in volume and mass as we view it from the ground, h thins <iut into space. Half of its density is tinder 16.000 feet. In a multitude of ways the air assists all living things to exist. Each of us is a creature of habits, but none of our habits is more vital to life than is breathing. So automatic and effortless is this habit that we give almost no thought to our respiration, although most of us cannot live without air for more than five minutes. From the second of our birth what we de scend from in utero (where the oxygen partial pressure corresponds to 33,000 feet altitude) into a world with a mature of gases called air, w*e must breathe several quarts of ah* each minute so our body cells can exist, grow, and perform their func tions. For an average lifetime of 70 years, we may breathe in excess of a half billion times. By contrast, we consume "three square meals'* and "six glasses of water" daily. Our air requirements which we obtain vir tually without effort are of greater signifi cance by any standards than water, food, clothing, and shelter, which demand much FUNCTIONS OF AIR Besides providing oxygen for breathingoxygen which lungs transfer to the bloodair conveys both sound and light, absorbs heat enables fires to burs, propels boats, turns windmills, makes possible ah* brakes, vacuum cloners, and other useful machines. Air in motion forms winds which modify climate, equalize heat and cold, and distri bute rainfall Rivers high in the air, such as the jet stream, greatly influence weather and are an increasingly important factor as air planes travel at higher altitudes. The ancient Greeks ranked air with earth, fire and water as one of (he four fundammtal elements. Since each of us has been breathing sev eral times each mmnte from our birth, res piratory protection and devices to aid or supplement breathing might seem unneces sary- If pure air were truly ubiquitous, and no harmful gases, vapors or dusts foisted. 11 1957 National Safety Congress Chemical Industries breathing problems 'would be cuufinrd to sources and appended to tins paper shows underwater or to travel m high altitudes. that respiratory problems have occurred in Unfortunately, pure air is a relatively rare many diverse activities. Specialized knowl commodity, and is much harder to obtain edge ad action in advance is essential if pure than many chemical elements and com such injuries are to be prevented. pounds. It is glamorous or unusual in Soane variations of the air are canvrf by natural forces (such as moisture from xaio or dust from winds on dry earth), while $nm^ are due to TM>n (such as combustion products, tmbumed or incompletely burned fuels, solvents, vapors, dusts, fumes, inert and toxic gases). When these variations are email, we say that the air as "pore,** but when the variations, either alone or in com bination, exceed our ability to adapt to them, or our abilhy to tolerate them, wc say the air is "had.** cidents which produce serious results; fail ure of a pressure system in an airplane at high altitudes will cause blackouts m sec onds; above 43,000 feet, even breathing pure oxygen is not adequate-- a pressure suit or a pressurized cabin is essential. On the other hand, no less serious are the problems when commonplace materials, such as a few sausages overheating and burning on a fry ing pan on a kitchen range produced suffi cient smoke and toxic gases to overcome the occupants; firemen required respiratory pro tective apparatus to effect a rescue of the air pollution unconscious victims. So simple yardstick has yet been devised /taw arwf smokes resulting fran fires to tell us when air ceases to be "pure," although numerous air pollution studies are underway, and threshold limit values (maxi mum allowable concentrations for industrial exposures) are available as a guide. We have just begun to realize that air pollution control may be even snore important than stream pollution control. When extreme conditions exist, as in London, Meuse, have been studied for years, and excellent reports are available, but it is impossible tc predict what gases may be encountered or in what concentrations in a give: fire. A large number of different flammable chemi cal compositions or chemical combinations that change with heat, such as plastics, fab rics insulation, refrigerants, solvents, paints. trwfttcitfcE and building materials, play im Danora or Los Angeles, we know that portant roles in our daily lives. foiman life is more difficult thzn other times when smog is not present. VARIETY OF GASS IN FIRES On a minor scale, every year a serious problem exists from dost or pcBat (such as rose fever, hay fever, or ragweed fever) for allergic persons, and we have found that respirators are frequently considered a a welcome supplemoU to dedication for the relief of such conditions. Jn OfMrtirm tO CZlboU mOQOXidc, CUboU dioxide, and water (presort in nearly all fires), one may expect ammonia from burn ing wool, cyanogqi from burning silk, ac rolein from burning fats, sulfur-containing gases from burning rubber and leather, and chknine-cantainmg gases from burning or smouldering chlorinated plastics. Tram paled Most breathing air supply problems can newspapers smouldering m limited oxygen, be controlled with adequate ventilation. If 41 per roe of the total gases given off was air could be properly treated to remove par found to be carbon monoxide, and 43 per ticulate natter, noxious vapors, and toxic cent was carbon dioxide. gases, bested or cooled, and then distributed A pole of newspapers in a large open ball- as required, breathing can be reduced to a tray would give an entirely different concen minor problem insofar as purity of air is tration of carbon monoxide and carbon concerned Unfortunately, adequate remUa- dioxide within the breathing zone than the tion and air treatment is sometimes impos sible or impractical where emergency action most he taken to preserve life and property. eymg pfo burning in a small enclosed base ment. Deienmnations ranging from two per fT* to lour per cent carbon monoxide Therefore, we must provide man with have been trade using recognized CO de respiratory protection if we expect him to tector* in the smoke of building fires in the survive. A glance at the case histories of same room in which firanen were engaged incidents collected at random from many in extinguishment, by a medical doctor 12 wearing self-contained breathing apparatus. Pneumonokonioses (Greek for lung dust) A vigorous movement is now underway to or pneumoconioses are a group of lung encourage fire and other rescue sendees to conditions which result from the inhalation nse adequate respiratory protection more of dust Silicosis is one of the most common effectively. types of pneumoconiosis, and is caused by AIR CONTAMINANTS The conventional classification of air con taminants follows: the inhalation of "free" or "unromhined" silica, such as quartz, opal flint and crysto- balhe. Many other dusts may produce long involvement such as ahsestos, talc, the sili A. Aerosols (dispersoids) (particulate contaminants)--dusts, fumes and mists. A better classification of aerosols is hosed on ph)*siologia] effects: A. Nuisance and Inert: produce no known injuries: calcium carbonate, magnesium carbonate, gypsum cates, carbon, iron and barium. Other dusts cause chemical irritation, such as the adds, alkali substances, fluorides and chromates. Allergic reactions may be caused by common dusts such as pollens, synthetic resins, plastics, felt, fur, gums, spices, to bacco, paper, rubber, wood, starch, floor, and wooL The Bureau of Mines groups alt the B. Inert pulmonary reactions: produce above dusts as "Fneumocomosis-Produang non-specific pulmonary reactions: sili and Nuisance Dusts-** cates, aliwrwmtrn C Minimal pulmonary fibrosis-producing barium compounds, tin, iron oxides D. Extensive pulmonary fibrous-producing silica, asbestos TOXIC OUSTS Another classification of dusts refers to `Toxic Dusts." Some have a louver thres hold limit or maximum allowable concentra tion than does lead, although the Boreas of E. Chemical Irritants: produce inflamma Mines classification uses lead as a reference. tion or ulceration alkaline reactions: Among aerosols more toxic than lead are: adds, fluorides, chromates cadmium oxide fume, chromic arid and F. Toxic systemic poisons: produce patho logical reactions: lead, manganese, anti mony, arsenic (not more toxic than chromates, mercury, mercury (organic), yellow phosphorus, picric arid, selenium, tellurium, calcium arsenate. Pb), arsenates, organic-phosphates, Respirators approved for all the above rarfinium, radjcactiv^ bayfijunj (more dusts (both toxic and pncumoconiosis-pTo- toxic than lead) ducing and nuisance dusts) are called "dust" G. Allergic manifestations: produce aller respirators. A few substances, such as beryl gic reactions: pollens. lium and radioactive substances, are not currently covered by Bureau of Mines H. Fever-producing reaction: action un schedules. . known or allergen: metal fumes, cer tain textile dust, (hemp, cotton, jute, "Fumes" include aerosols formed by the bagasse) condensation of vapors from heated metals. Melting. cutting, and welding of rinr, lead. A. AEROSOLS i-admiu w and o&er mtah produce sadi Formerly called dispersoids or particulate fumes. contaminants, these are substances present in "Mists" and "Sprays" include liquid drop- the air as minute particles (such as dusts), jets formed wfiox liquids are carried into as fumes (such as metal /times), or as ousts the air or are formed by a reaction with (such as chromic-add mists). In grouping the moisture in the air. An interesting ex these together, it is recognized that they ample is OJ parts per minion sulfur dioxide, may be physically filtered, screened, or ad with sunlight, forms 20,000 particles per cc sorbed from the air with properly d^g**** of sulfuric arid mist. filters. Aerosols may range m sue item The araSahafity of fillers with pore sizes \50 microns to a fhttisandth of % micron in from lti mtilrmicrons (appitodmalely the size (1 micron equals 39.37 millionths of an size of the polio virus) to five microns (the inch mix 10-4 centimeter'). Many dusts size of common coctammants in liquids) are aim fire and explosion hazards. has greatly unproved and speeded up analyses 13 1957 National Safety Congress of aerosols such as add mists, metal fumes, smokes, and radioactivity. Id twmt years, study and measurements of even smaller particles is air than pre viously observed, known as condensation nuclei, have contributed greatly to oar under standing of the nature and number of pani cles in air. The particles in the air on wrhldi water will condense are called condensation nuclei; under natural conditions only the larger panicles are so effective. When the air is sufficiently super-saturated apparently any partide will serve as a condensation center. Particles from such diverse substances as platinum, silver, stearic arid, glycerin and lubricating oil will all form droplets at a sufficiently high supersaturation of water vapor. Practical methods are now available to measure the number of particles m an aerosol in free air. A wider use of the technique already available for sue and numbers of an aerosol would not only throw* light on some of the problems of air pol lution but would certainly lead to further improvements in our knowledge of aerosols. Respirators for insecticides are tested and listed by the U. S. Dcpartmait of Agricul ture. B. GASES AND VAPORS In this major group may be included most of the air contaminants which are not classi fied as aerosols. ]. Irntani gases are those which produce inflammation of tissue, such as the skin, the eyes, and the respiratory tract membranes. They are divided into two general groups: a. action is limited to irratian (such as hydrogen choride) b. action extends to systemic effect (such as oxides of nitrogen) Some of these gases and vapors have pro nounced odors, but the nose Gumot be depended upon as a reliable method of es timating concentrations. 2. Asphyxiants are substances which de prive the body tissues of oxygen, causing hypoxia (oxygen starvation). Two general methods of action are known: simple asphyxiants (such as nitrogen, hydrogen, helium, and methane), which dilute or re place the oxygen partial pressure in air; and chemical asphyxiants (suds as carbon mon oxide, hydrogen cyanide, hydrogen sulfide, acetonitrile, aromatic nitro and amino com pounds like aniline, nitrobenzene and deriva tives), which combine with the hemoglobin of the blocd to prevent oxygen-carbon diox ide exchange. The insidious nature of the actios of the simple asphyxiants, and the speed with which they can act, is still not widely appre ciated; whereas most people have a healthy respect for the chemical asphyxiants. Under proper medical supervision, jiure nitrogen may be brathed for several seconds and this technique has been used clinically by* Himwidi and others. However, nitrogen and the other simple asphyxiants give almost no warning between the time breathing air is replaced with the asphyxiant and uncon sciousness overtakes the subject PHYSICAL REACTIONS A. loss of mental facilities begins within a few seconds, and unconsciousness may occur shortly after with no warning. The brain is the first organ of the body to be affected seriously by oxygen want, and the subject "blacks out** quickly*. Morion is made of this little-appreciated phenomenon not only because asphyxiants can be released in a room or tank with inadequate warning from the action of a fixed carbon dioxide fire extinguishing system, from a large spill of liquid nitrogen, from a leaking gas sys tem, from an inert-gas producer, or from a leaking cylinder, but also because airlinesupplied respirators, hoods and suits are frequently* attached to a plant air supply with little appreciation of the hazard. For example, at the Adds and Havy Chemicals sub-section meeting. Chemical section, National Safety Council, October 25. 1956, no company present reported use of a special air system for respiratory equip ment. If a cross-connection should occur anywhere in the air system which would permit an asphyxiant toxic, or flammable gas to enter the an- used for breathing, the results can easily and rapidly be fatal. Oxygen, used indiscriminately, may also be a hazard, since serious fires have been reported where oxygen, either from a cylin der or an airline, or a leaking hose or pipe, was used for breathing purposes in an air line respirator or hood where welding or other flames were involved. Only a com 14 Chemical Industries pletely separate air supply, supplied by a compressor which cannot evolve carbon mon oxide, carbon dioxide, off mist or other un wanted impurities or from cylinders of tested known purity should be used for air line respirators, hoods or suits. In any event, regardless of supply, the system should include pressure relief valves, filters and absorbents as recommended. 2. Anaesthetics are gases and vapors whose action is primarily by inducing the symptoms of anaesthesia when inlialed in sufficient quantities. These include the sub stances which come to mind when the word "anaesthetics** is mentioned, such as the ethers, chloroform, methyl chloroform (1,1,1(richlorocthane), trichloroethylene, ethylene oxide and nitrous oxide (laughing gas), as well as hydrocarbons, aldehydes, ketones, other halogenated hy'droearbons. the aro matic hydrocarbons, alcohols, esters, and carbon disulfide. DECOMPOSITION OCCURS In addition to the physiological action of these materials alone and in combination, decomposition products are produced in a fire or when they are otherwise subjected to heat. Even relatively harmless substances such as the Freons and the Genetrons, (widely used as non-flammable refrigerants of low toxicity, as rcplacanents for am monia, sulfur and ethane), will evolve toxic decomposition products if they are hated above their decomposition temperatures. This las occurred where Freons and Genetrons were used as cleaning solvents. Metal parts, after cleaning, were hated above the safe limits in order to dry* and flash off the remaining solvent. Several persons were hospitalized with pulmonary congestion. Trichloroethylene degrrasers, properly installed, maintained and operated, are safe, yet the failure or misuse of these vapor degreasers has crated serious haz ards including both fires and toxicity*. Mass hysteria and unconsciousness due to the little-appreciated anaesthetic action of the trichloroethylene has occurred in sec onds; in one incident 72 person5 were over come, and in another, 26. Fortunately, all recovered after removal to fresh air and oxygen inhalation. The hazards of carbon tetrachloride mixtures in fire fighting and in other applications are well documented. 4. Substances producing other effects-- This classification includes several substances whose action differ from previously-men tioned substances. Included in this group are mercury, white phosphorus, tetraethyllad, nickel carbonyl, arsine, the bona hy drides, phosphine, hydrogen sulfide, and the widely-publicized military "nerve gases.** The initial action of these gases and vapors is primarily on the nervous system, with respiratory* arrest following. contaminants combine If the above classifications appear com plicated, it must be remembered that these air contaminants seldom occur alone, and that even less is known about the combined action of two or more substances, especially if they are in different groups, than of the individual substances. Even if particles in the air are non-toxic in themselves, they are knows to act as carriers of condensable toxic vapors--formaldehyde can have its toxicity' increased five times by the presence of an aerosol It is little wonder, then, that respiratory protection can become a highly complicated subject, and that the practical application of respirators, gas masks, and self-contained breathing apparatus (all with their limita tions), even by persons thoroughly trained in their use. Is not cut-and-dried or fool proof. Relatively untrained persons in an emer gency* situation, are in especially vulnerable positions. Many of the case histories at tached to this paper dearly point to the need for more widespread appreciation of the nature of the hazard, as well as of the limits of the various respiratory* protective equipment used. RESPIRATORY PROTECTIVE DEVICES A. AIR-PURIFYING RESPIRATORS The fundamental limitations of any* air purifying device are that the air must be within the limits for which the respirator was designed (for example, the oxygen content must be more than 16 per cent) ; the particular trait will only protect against the specific substance or combinations for which it was designed, (for example, aero sol Idispersoid] (filter type] respirators will give no protection against gases and vapors); and the canister or filter must be 15 7957 National Safety Congress maintained in proper working condition (an reduced where higher concentrations of mer a properly maintained facepiece that fits cury from elevated temperatures and pres snugly enough to exclude lealage). sures are present. (There is no Bureau of Aerosol (filter type) respirators require Mines approval schedule for mercury res frequent changes in fibers when breathing pirators). Combination cartridges have the resistance becomes uncomfortable when used where excessive dust or fumes are involved. Chemical cartridge respirators will safely protea only against the specific vapors and limitation of a shorter service life when used with one particular type of hazard than the equivalent specific single-purpose canister would have for the same hazard. gases in non-emergency situations where no more than 0.1 per cent is encountered Extremely toxic materials, such as acro lein, acrylonitrile, aniline, dimethylamline. a:;ine, bromine, carbon disulfide, carbon monoxide, dnnethylsuliate, hydrogen cyan* ide, hydrogen fluoride, hydrogen selenide, hydrogen sulfide, iodine, methyl bromide, methyl chloride; nickel and iron carbonyl, tutrobaHene, nitroglycerine, niiromethane, oxides of nitrogen, ozone, phosgene, phos phine, phosphorus, trichloride, siibine, sulfur chloride, the boron hydrides and others are too toxic even in low concentrations for re liance to be placed on simple cartridge type respirators. FACEPIECE TYPES Normally, respirators use a "half-mask" facepiece, covering the nose and mouth, while gas masks use both full-masks and full facepieces. (Only full facepieces on gas masks are approved by the Burnt of Mines). Recently, the "seli-rescue** or "pocka" respirator, normally used with a cartridge containing Hopcalite with a dryer and designed for escape from mines, has been extended into other cartridges. The mouthpiece of this style respirator is held tightly by the front teeth of the wearer, and'the breathing is accomplished through the mouth. A nose damp blocks off the opaiings of the nostrils, and prevents irri NOT FOR ODORLESS GASES tation of the membranes of the nose. A Chemical cartridge respirators should not be used against gases which arc odorless or whose odor threshold is high, since the only warning of failure of the respirator or neckband permits the respirator to be worn ready for instant use. Twelve diffenmt filter cartridges will fit the basic holder and mouthpiece. of concentrations which are above the ability Industrial canister-type gas masks, with of the respirator is odor. Methyl chloride canisters designed for specific substances or is as example of such a gas whose warning combinations, have the same limitations in properties are too slight for practical pur* gcncTil as chemical cartridge respirators, poses. Substances which are highly irritat except they arc effective in concentrations of ing to the eyes, such as sulfur dioxide, re any specific gas or members of the same quire eye protection (such as a gaslight group of gases for which the}* are designed goggle, an air-supplied hood, or a xuli-face- of not more than two per cent in air or a piece). two per cent total for a mixture `of gases Several lacrimalory (tear-producing) sub- for which the canister is designed. tances, such as benzvi chloride, are in the The ammonia canister is approved for same classification, and a respirator alone three per cent ammonia. For shorter periods is dearly inadequate. Some substances, such of tune, industrial canister-type gas masks as carbon monoxide, cannot be stopped by can be used in higher concentrations, but a chemical cartridge (except by the Hop- the time of service life will be reduced. calite in the Tjpe X universal gas mask Depending on the size of the canister, and and in the miner's pocket self-rescuer). the service for which it was designed, the Ammonia cartridge respirators will protect service time varies. against ammonia up to 1,000 p.pm, while eye irritation from ammonia begins at about 700 p.pm. Protection for a combination of various gases, such as add gases, organic vapors, and ammonia raw all be obtained in one Mercury cartridge respirators are effec canister, but the service life of such a tive against concentrations of mercury vapor combination is shorter in the combined can normally encountered at ambient tempera ister when used with one specific substance, tures, but service life is proportionately than is the life of an cquivaloit canister 16 Chemical Industries designed for specific substance alone. The only wanting that a canister or cartridge is "exhausted" is the detection of odor of vapor or gas passing through the canister or ortridge. Persons who need corrective lenses m order to work properly when wearing the respiratory protection, especially full face pieces, may find of interest two methods of incorporating lenses inside a facepiece. One method consists of wire frames which fit around the dragnferencc of the sight lenses, and hold a 30-mm round prescription lens. PRESCRIPTIONS IN FACEPIECES A second method consists of a center post built inside the mask, onto which can be attached 40mm rimless glasses. Such arrangements seldom allow perfect align ment of the prescription lenses to the view ers eyes. but. with adjustment, a sufficiently accurate fitting can be achieved for most purposes for reasonably long periods of time. The type X universal gas mask canister is constructed of several lasers including activated carbon (to remove organic vapors), soda lime (to remove arid gases and carbon dioxide), copper sulfate (to protea against ammonia gas), silica gel and other dryers (to remove moisture both before and after the Hopcalite). and Hopcalite itself (a mix ture of metallic oxides which catalyzes the conversion of carbon monoxide to carbon dioxide), plus a filler for smokes. This canister on be used as protection against smoke and gases which do not ex ceed two per cent by volume total, where adequate amounts of oxygen are present Sixteen per cent oxygen Is died as the practical minimum, but life is not actually in danger until about 14 per cent or less oxygen is present. A timer is used to count the number of inhalations, and indicates about two hours total use. DISPOSE OF CANISTERS A canister should be discarded at least as soon as the timer indicates the pointer has completed one revolution, if not sooner. One authority recommends that universal canisters be weighed immediately on re ceipt from the manufacturer, and tliat the}* be discarded as soon as they have gained 45 grams. This 43 grams limit was imposed since it represents the limit of the dryers to keep the Hopcalite dry** and also to prevent excessive breathing resistance from developing as the dryer becomes most The shelf-life of the universal canister, once the canister has been attached to the facepiece is one yor, if stored with the bottom seal in place, even though the mask has not been used. If stored with both top and bottom seals unopened, as received from the manufacturer, the shelf-life is considered by some to be four, and by others, five years. With an respirator or gas mask, the prob lem of proper fitting of the facepiece is critical. In addition to the time honored technique of holding the hand over the opening in the bottom of the canister while inhaling gorily to see that the facepiece will collapse on the face, another technique re cently suggested bv tire A-E.C is to use isoamvl acetate. Since isoamyl acetate (which smells sim ilar to bananas) can be detected in a con centration of as low as one part per mil lion, a small leak will be detected if the acetate is placed on cotton and the cotton passed slowly around the edges of the mask without touching other the wearer's face or the mask. If the wearer can detea the odor, a leak is indicated and the mask should be further adjusted until the odor can no longer be detected. CIVIL DEFENSE MASKS As part of its chemical' warfare defense program, the Federal Gvil Defense Ad ministration is stockpiling a mask desig nated as CD V-SOO organizational mask far use by aril defense personnel. The canister on this chin-style mask is tlte same as used in the U. 5. Arm}' Assault Made. This mask is reported to give "excellent pro tection against CW (Chemical Warfare) and B\V (Biological Warfare) agents, as well as against the inhalation of radio logical particles, or CBR (chemical, bio logical and radiological)*'. Designed to be used in conjunction witba detection kh, CD V-610, which will detea and distinguish between the nerve gases and the mustard gases, the V-800 mask is a specific mask for war gases (including nerve gases) and will not protea against carbon monoxide, ammonia and other gases. Tlie Army Chemical Corps recently an- 17 1957 National Safety Congress Pounced a sew -13 mask for troops. It is designed to give the soldier complete protection against the inhalation of scar gases, germ warfare agents and airborne radioactive fallout particles, but does sot protect against direct radiation. The new mask does not have the pro truding canister used in current masks. This seas made possible through develop ment by the Chemical Corps of a new light-weight pliable gas-aerosol filter ma terial. Pads of this material are enclosed within cavities molded into the robber face piece of the mask. Lower breathing re sistance, superior vision, better speeth trans mission, and greater comfort are claimed. It should be noted that the CD V-800, the existing and the new Army gas masks should be used for purposes for which they were designed only. After both World War I and Tt several instances were reported where "surplus*' Army masks were used for protection against gases for which they were not designed, with serious conse quences. It Is important that gas masks are not misused. B. AJR-SUPPUED RESPIRATORS gmre the simplest solution to all respira tory problems is to supply pure air to the brother, the use of an air supply from some remote source where the air is not contaminated is both simple and logical For many applications, air-supplied equip ment has real advantages, but this equip ment is subject to definite limitations. The simplest type is the Bureau of Mines Type B hose mask, which is a facepiece to which is attached a hose without a blower which must extend to a respirable source of air. This mask depends on the breathing action of the wearer to move the air. For this reason, a Twa^-iynum hose length of /a feet been established for the hose mask with out blower. Low pressure Mowers, operated either by temrl or by power (power blowers do not carry Bureau of Mines approval) are used to supply Bureau of Mines Type A hose casks up to 150 feet All hoses should originate at the blower. A respirable source of air must be as sured, and a safety man must be present ct tin; blower at all times. Fouling of the hose may art off the air supply, and the ^ptt route must be the same as the entrance 18 route. These hose masks can be used safely only if the above precautions are observed. Afrlme-snppUed Bureau of Mines Type C respirators are divided into two classes: (a) the continuous flow type and (b) A* donand or intermittent demand flow type; (a) is usually used with a powered compressor or blower, while (b) is usually used with breathing air supplied from cylinders. The use of such equipment in atmospheres im mediately hazardous to life is not recom mended <twr failure of the air supply or fooling of the hose would be serious, and further, it is absolutely necessary to have respirable air of unquestioned quality. We have previously noted the hazard of using a jdarit air supply for air-supplied breathing equipment. It is recommended that a separate air system be used exclu sively for breathing air. Depending on the pressure available and the diameter of the hose, there is a limit to the length of hose which is practical Wherever possible, such systems should be piped as close to the outlet as possible so possibility of fouling of the hose and cutting off the air supply will be minimized. Exit from areas where air-line respirators are used tenst, of course, be the same as the route in. If a compressor or tank sup ply is sufficient pressure relief control must be available to protect the w*earer apma pressure in excess of that prescribed for the equipment AlfUNRATH) SUnS Air helmets, air books, and air-supplied suit; hare the same general limitations as for air-line respirators. An interesting de velopment in this field is the use of airinflated suits for protection of the whole body against hazardous materials. To form, the large impervious plastic tunnel or pipe allows a man to work in one room while using air from another-- the slight air pressure supplied giving both breathing air and inflation (or body) to the suit The front of the suit is tailored into a facepiece, and arms with gloves are at tached. Mobility is reported good within the obvious limits imposed by the length of the rwnn#! attached. In another form, a complete suit with buflt-m arms and legs is supplied with air for inflation and a hood, also air supplied, Chemical Industries is used for head, face and respiratory pro tection. Depending on the particular fabric, plastic, or composition used in its construc tion, this suit allows work inside tanks, reaction vessels and other confined space which still contain a hazardous atmosphere. Properly used, together with safeguards to insure that the wearer's air supply and life line are always in proper position and work ing order, this suit has increased safety and decreased operating costs in maintenance work inside tanks containing materials which are corrosive or are easily absorbed through the skin such as aromatic ammo and nitro compounds. The same limitations noted above for air-line respirators should be noted. Regardless of the type "respirator** used, a definite program of control is nccessarv to insure the device is used properly, is prop erly maintained, and that it is doing what is expected of it After the CkJk River atomic reactor incident, respirators were used to prevent inhalation of radio active contaminants. This program was suc cessful only after a respirator official was appointed to control the use and mainte nance of respirators, regular urine-samples were analyzed to show definitely the degree of absorption, and an improved respirator was made available. C SELF-COSTAIKED BREATHING APPARATUS Self-contained breathing apparatus supply complete respiratory protection in any con centration of toxic gases and under any oxygen deficient atmosphere. However, cer tain gases and vapor will cause systemic poisoning by skin absorption. Although a small group, these exceptions are highly important, including hydrogen cyanide, nitro and amino aromatic compounds, ethylene inline, phenols and a few others. These gases and vapors require complete skin protection of an impervious type in addi tion to respiratory* protection. EARLY RBREATH1NG APPARATUS The early self-contained rebreathing ap paratus which was imported from Europe, had serious deficiencies. Loss of life was reported by users in this country; 19 acci dents are reported involving 26 facilities between 1911 and 1940, due partly to equip ment failure and partly to improper use. IVhere life-lines and standby rescue squads were employed, the apparatus was generally satisfactory in the hands of well-trained users. The first self-contained breathing appa ratus to be approved by the U. S. Bureau of Mines was of the two-hour rebreathing type. The oxygen rebreathing type apparatus is relatively heavy (39# for the two-hour type) and is bulky. Most self-contained (dosed circuit) oxygen breathing appara tus in use today require mouth breathing with a nose dip, but a full facepiece has recently been approved. Careful training is required in use and is maintenance of this apparatus. A minimum of 20 hours initial training is recomnusided by the Bu reau of Mines. RESTRICTS MOVEMENT Demand-type air and demand-type oxygen breathing apparatus is available in half-hour, quarter-hour and 7)6 minute ratings. Only the half-hour demand apparatus is Bureau of Mines approved; the Bureau has no approval schedule at present for any self- contained apparatus of less a half-hour. Although the schedule of work on which the Bureau's half-hour rating is exhaust ing. large men under enymif stress have exhausted a half-hour (40 cu. ft.) cylinder in significantly less than a half-hour. Differing only in whether it is supplied with compressed oxygen or compressed air, the apparatus weighs nearly 30 pounds for the half-hour type, with the large cylinder (40 cubic feet) on the back. It is relatively awkward to put on and it restricts action in confined spaces. With practice, it may be put an and into operation from a mounted backboard in less than 20 The bad; position of the cylinder makes H difficult to craw] under equipment. Climb ing in and out of small openmgs, such as manholes, requires care when wearing this type apparatus. Operation of a motor ve hicle is awkward when wearing a cylinder on the back. (15-minute and 7)4-numite donand apparatus use gmallw* cylinders slung on the side of the wearer, which overcomes this objection to some extort.) The purity of the air or oxygen with which the cylinder has been charged should always be questioned since other gases such 19 193/ National Safely Congress as nitrogen, acetylene and carbon dioxide and gas mixtures other than air have ac tually been found in "breathing air" cylin ders. Errors in compressed air used for breathing may be rapidly fatal, and every newly-filled cylinder should be checked to insure it actually contains "breathing air/' regardless of the source of supply. Unless the user has his own compressor producing air of an unquestioned purity, no cylinder should lie put on a demand breath ing apparatus or air-supplied respirator, hood or suit until the contents have lieen checked for purity. The Orsat gas analyzer or the Beckman paramagnetic oxygen ana lyzer are often used in analyzing oxygen percentage while carbon monoxide may be checked with the National Bureau of Stand ards colormetric tester available from two manufacturers. High pressure cylinders may leak, and frequent inspection is necessary to insure that the air or oxygen is actually available for use in an emergency. High pressure valve, gauge, and demand regulator must be maintained in top operating condition by inspection and a regular preventative maintenance schedule as recommended by the manufacturer. atmosphere cuts service If demand-type apparatus is worn in environments where pressure altove one at mosphere is presort (as in caissons or tun nels under higher than atmospheric pres sure), the service time is reduced as the pressure increases. This is also true of un derwater use of the regular demand-type apparatus; a special adaption is available tor underwater swimming. Other peculiar effects have been retorted when demand and dosed circuit oxygen breathing apparatus was worn under pressure. The use of oxygen in atmospheres above two atmospheres absolute pressure should be avoided since oxygen produces a toxic effect under such conditions. For periods up to 12 hours at normal atmosphere pres sures, however, oxygen may be used without apparent ill effects by healthy persons-- persons in questionable physical condition should not wear any emergency breathing equipment, but should remain away from contaminated air and underwater. When the supply of air or oxygen has been depleted, the supply in the demand type ajrparatus cuts off abruptly, and the face piece must he removed immediately or asphyxia can occur. One British half-hour breathing apparatus has available as op tional equipment an automatic warning whistle (PaL No. 644105) which will start to blow when the cylinder pressure falls to 300 pound/squarc inch, to aid in warning the wearer to return to fresh air at once. The seal around the facepiece must be absolutely gas-tight in a toxic atmosphere since in the demand-type apparatus the iacepicce is under slight negative pressure momentarily during the beginning of the inspiration pltase of the cycle. A recent revision bv one manufacturer eliminates this negative pressure pan of the cycle. Another novel feature of another demand mask (54 cubic feet of air or oxygen di vided lictween two 26 cubic foot cylinders for balance) is a plug-in attachment car ried with the mask for administering re suscitation to an overcome person on-the-spot while still in a toxic atmosphere. In the alove discussions, no mention has l*eai made of the tire and explosion hazard of air which is richer than 21 per cent in oxygen, or of pure oxygen itself. Certainly air should not l*c replaced with oxygen, either in a breathing apparatus, in a ventila tion technique, or for any oilier purpose, without full consideration of the increased jtotcaiiial liazards from fire, as the oxygen concentration increases above the 21 per cent oxygen content of air. A flammable vapor-oxygen mixture requires only about one thousandth the energy to ignite it as does a corresponding flammable vapor-air mixture. The resulting fire or explosion is many times more violent. Failure to appreciate these facts (which have been published and well documented for years) lias cost many lives. For this reason, it is as important to analyze a suspected atmosphere for oxy gen concentration as for flammable vapors and gases, and for toxic gases. By using either tlie time-honored mine safety lamp as an oxygen indicator, or the more re cently available Beckman paramagnetic oxy gen analyzer, it is possible to obtain fast and sufficiently accurate oxygen analyses for practical purposes. Combine such oxygen analysis (which will reflect inert gases or oxygen deficient at mospheres as well as excessively high oxy 20 Chetnieal Industries gen concentrations) with a check for flam mable vapors and gases (using one of the many instruments commercially available), and a check for whatever toxic gas is suspected (for CO. for example, the Na tional Bureau of Standards glass tubes con taining palladium chloride which changes color with CO). To ignore any one of these fundamentals is to run risk of trouble. must be exercised to avoid cuts from the tom top seal when removing it, and the canister brouglit securely into place after it has lieen punctured by the sharp point designed into the apparatus for that purpose. The facepiece should not be donned until the canister is completely sealed. A fresh canister should always be used in any emergency. Safe 45 minutes The self-contained oxygen-generating breathing apparatus is approved by the Bureau of Mines, and is rated for 45 min utes. Some of the models produced for the military are not Bureau of Mines ap proved, however. 77* weight of 14#, car ried on the chest and stomach, gives it a decided advantage Imth in weight and con venience over the demand-type apparatus, although the chest position creates limita tions in use under some conditions. The highly exothermic reaction, which generates oxygen from the potassium super oxide (K*0) evolves significant heat, which might sene as an auto-ignition source to carlon-disulfide or nickel carliony] vapors under extreme conditions. This tempera ture of the canister surface may reach 250*F, and is equivalent to the liazard pre sented by unshielded incandescent lamps, hot plates and steam pipes in such an atmosphere. When worn in hot areas, or while work ing hard m the heat, the oxygen generated may occupy a volume which requires "dumping" oi surplus oxygen to maintain comfort. The apparatus requires care in starting, especially in sub-freezing tempera tures--for this reason it is considered good practice that both the apparatus and the canisters be stored inside or in a heated truck cab or automobile, and that the ap paratus be thoroughly started above freez ing temperatures, it possible. Unless the sub-freezing starting is thor ough, the wearer may be aware of insuffi cient oxygen during the first few minutes, by a feeling of "light headedness" and diffi culty in coordination. If such a condition is noted, he should return to fresh air, deflate the bags and re-stan the apparatus, until the breathing rate and the generating rate balance before re-entry. In inserting the canister in the canister holder (canister is stored separately), care Once opened, a canister will continue to evolve oxygen even when removed from the apparatus and re-capped To enter a hazardous atmosphere with a used canister is a highly dangerous practice--a fresh canister must le employed to insure safety. In view of the relatively high cost of these canisters, the temptation to re-use canisters is great, but should lie avoided, and canisters promptly disced of to insure the safety of the next user. DON'T RE-USE CANISTERS The disposal of the self-contained oxygen generating canisters must be performed ac cording to the instructions. Oil, grease, gaso line. or other flammable or combustible liquids must be kept from the canister mouth, or an explosion will occur. Only clran water in large quantities should be used to destroy a canister. The canisters should be promptly disposed of, and not be left sitting around where they* could contact combustibles. For reasons noted under discussion of demand-type breathing apparatus, the selfcontained oxygen-generating apparatus should not be worn under pressures greater than two atmospheres absolute. Smaller Self-Contained Breathing and Oxygen Inhalation Devices U. S. Bureau of Mines approval for self- contained breathing apparatus currently makes no provision for apparatus rated for less than 30 minutes. In emergencies where a smaller, less cumbersome device with a shorter Hie would give adequate protection, the only available devices until recently were regular demand masks with smaller cylinders for 20, 15, and minutes serv ice, using the same facepiece, reducers and regulators as on the larger approved devices. Recognizing that many (perhaps most) breathing emergencies can be brought under control in 10 minutes, and that the first 130cc of expired air contains relatively lit- 21 L r-\M 'I'- - 1957 ATational Safety Congress tie CO*, there is now available a light weight device in which oxygen from snail cylinders, supplemented by the first lOOce of the previous exhaled breath, is used for breathing at a rate of seven liters per min ute. The device is still too new for exten sive field experience, but represents a novel and new approach to the weight, bulk and cost of presently approved equipment. Another recent development is a small portable anaesthesia and oxygen breathing device which is designed for use by medical personnel primarily, but which has obvious application as a "self-rescuer" for escaping toxic atmospheres. The device consists of a face piece with pressure limiting valve, an aluminum central body, a soda lime canister m volumes of lOOce to SOOcc, two alummum cylinders, each containing three liters of oxygen, and a six liter rubber rebreathing bag. Using the device for escape, it is claimed a young male adult walking three mph can travel safely for 1100 yards using a 200cc soda Lime canister, and 1600 yards using a 500cc canister. Since the complete unit weighs less than two pounds, and the oxy gen cylinders are pocket-size, the device may rightly be oiled pocket-size, and, in the bands of trained personnel, should be useful for self-rescue oxygen inhalation or resuscitation. Maintenance, Training and Medical Precautions In dlcmesing respiratory protection, we have shown the importance of breathing "good" air, briefly reviewed the major air contaminants, and discussed briefly appara tus available. We have stressed the limita tions of each type, rather than the advan tages, since we believe that limitations were not as widely appreciated as advantages. The ideal breathing apparatus has yet to be developed. We have tried to create the im pression that a thorough knowledge of the particular apparatus used is essential for its safe use under various conditions. Maintenance of the apparatus in first-class condition so it is immediately ready for use at any time as likewise important. Metal parts of apparatus will wear, tarnish or corrode; rubber parts will slowly "age." Facepieces will take a "set" and must be discarded. Cylinders, regulators and valves on demand-type apparatus must be checked frequently for leaks; canisters cm industrial or universal service masks or chemical canridge respirators must be replaced. Washing the facepiece with an antiseptic solution or soap, rinsing m dear water, and drying will assure that sanitation and clean liness is not neglected. This also prolongs the useful life of the facepieces. Proper storage conditions and frequent checking for deterioration are as important with respira tory protective equipment as with fire ex tinguishers, parachutes and life-lines. TRAINING deficient Training is the third, and perhaps most important leg of the triangle of respiratory safety. There is serious deficiency in this phase of the respiratory' program. Putting on a device for a few minutes once a year is not adequate training. The U. S. Burrau of Mines Health and Safety Activities, through its district and sub-district offices, conducts training courses in first-aid, and also in the use of various eroergcicy breath ing apparatus. The course can be modified to meet spe cial needs on request. Addresses of offices which offer these courses may be obtained by contacting the Health and Safety Divi sion of the Bureau of Mines, 4600 Forbes Su Pittsburgh 13, Pa. This service of the Bureau is available to the mineral and allied industries, as well as to governmental agencies. The Bureau has at cadi of its Health and Safety field offices throughout the country* mine-rescue equipment, and will make it available to trained personnel in any emergency. During training, breathing apparatus should be worn for relatively long periods, in dark and confined spaces, climbing hills or stairs, duplicating all manual labor ex pected, and in smoke-filled atmospheres by hand-carried lights while performing work. Smoke generators are available, w*hich win quickly fill a roam. a. basement, a tunnel or a small building with a smoke that is real istic, but which is relatively harmless and can be ventilated out without any damage. The "buddy" system and team drill should be practiced, as in a Teal emergency. The use of life lines should be a part of this training, and should be a standard part of any underground, tank or smoky operation. 22 Chemical Industries Signals as used by mine rescue teams based on OATH <0=0K=1 pull; A~ad- CASE HISTORIES vance=2 pulls; T-tafce-up=3 pulls; H= AMMONIA help=4 pulls) should be employed and The incident in question took place in stand-by men, ready to enter the area for Singapore, Malaya, during the early days rescue, should always be oo hand. of die war 1942, just prior to the fall of the Hand-carried short-wave two-way radios city to the Japanese. may also prove useful for communication Our ship was tied alongside the docks, between base and field party. When used having just completed a mission. The city in atmospheres wliich may contain flammable was under air attack Continually, so that we vapors or gases, any electrical devices should maintained a full scale Battle Watch, Teady have a "permissible" rating by the Bureau for any emergency. It was after one of of Mines for the gases or vapors involved. these raids that a strong odor of amnvmta was observed on our ship; our blower venti PHY5ICAL EXAMS LACKING lating system was picking h up. Investiga The need for proper physical examina tions for persons wearing emergency equip ment has not always been appreciated in the past. A regular program of physical check ups with particular attention to the respira tion by our shore patrol informed us that a large cold storage plant lad been hit and that the local fire department was attempting to rescue several members who were trapped inside the buildings. tory and circulatory system as well as Our fire and rescue section was dis general physical condition probably would patched to the scene at once; we were have prevented some cases where inhalation equipped for such work with demand-type of a smoke combined with physical breathing apparatus, with proper protective with or without respiratory protection, has equipment and safety lines. Upon arrival we produced serious illness. were briefed as to the plant layout and the Pulse rates before, during and after ex ercise, general physical condition, moderate weight, good eyesight and proper teeth aliuement (where mouthpiece breathing is in volved) are considered vital to pre-training by the Bureau of Alines instructors. A practice of not permitting persons to return unprotected to smoke or fames after they have been overcome and revived, would help prevent more serious inhalation effects. Such restraining action may require physi cal force to implement h in practice, since a patient who is partially recovered from iume or smoke inhalation may display highly possible location of 10 men inside the build ing with a British fjpe canister mask for protection. We entered the area working in pairs, and during the next 20 minutes removed 10 firemen, who had been well trained by the best of British methods, but unfortunately ill equipped for such violent conditions. When found, all mm were unconscious and upon removal from the building were rushed to the hospital, oxygen being admin istered earoute by a fine Australian medical team. Of the 10 men rescued, six died from the effects of ammonia inhalation, four men recovered completely. irregular behavior. One recommendation is that persons sufficiently exposed to smoke and carbon monoxide to require tTgtmcnl should not return to active duty in less than four to six hours, while those who have been rendered semiconscious or unconscious should rest 24 to 46 hours. During the entire operation none of our team experienced any breathing difficulty; the teaching of damage control, fire and rescue work by Naval standards are very good. Their careful selection of reliable equipment has been the result of carefnl re search and experience. Properl}' maintained breathing apparatus, used with full appreciation of its limita NITROGEN IN A1R-UNE tions, by healthy persons, properly and ade RESPIRATOR quately trained, will eliminate most "fmne" disabilities in the future. However, the ideal breathing apparatus for all applications has Employees in an area were required to use air-line respirators as a precaution against inhalation of radioactive particles. not been developed, and maj- not be devel The air line was also used to provide in oped until there is sufficient demand for it strument air. 1957 Kalional Safety Congress FILMS 1. Mechanisms of Breathing (EBF) 612.7-1, Pennyslvwnia State University, Audio Visual Aids library. State College, Pa. or Encyc. Brit. Kims, Inc. 1150 Wil mette Ave- Wihnene, I1L, (16mm sound. 11 tnin). 2. Oxygen, 16mm sound, 10 min_, B&W and color. Coronet Films, Coronet Bldg. Chicago 1, 111. 3. The Air IfV Breathe, 16mm sound, 26 min- B&W; Mine Safety Appliance Co5-45 49th Ave- Long Island City, S. Y. or local sales otrice. 4. The City That Disappears (Los Angeles), 16mm sound, color, 30 min, (Stanford Research Institute, Menlo Park, Calit. 5. A Report on Smog, 16mm sound, color, 20 min. (same source a* 4). 6. You Bet Your Life, 25 min., 16mm sound B&W, available same source as 3. 7. Use of Oxygen in Aviation, TFl-4595, 22 tnin- 16mm sound, color, same source as fi. " ^ 8. Oxygen, In-Flight Requirements, TF-1-5Q3SA, 25 min- I6nun sound, color. Air Force Training Films, Eastern Film Exchange. 1356 Film Library Flight (APCS) (MATS), Marietta Air Force Station, Marietta, Pa. 9. Oxygen-Jn-Fligkt Equipment, TF 1-5038B, 30 min, 16mm sound color, same source as 6. 10. The Physiology of Anoxia, 30 win. 16mm sound, B&W, same source as II. 11. The Breath of Life, 10 min, 16mm sound color. H. T. Polk, Oxygen Therapy Dept- Linde Air Prod. Div- L.C.&C- 30 E. 42nd St. New York 17, N V. 12. Safe and Efficient Oxygen Therapy, 20 min- 16mm sound color, avail, same source as 11. 13. Sitrogen Inhalation Therapy, 10 min- 16mm rilett color, "Dr. H. E Huuwicb, Galesburg State Research Hospital, Galesburg. 111. 14. Sokey Chlorine Emergency Deziees, 16mm silent coIot, 40 min- Research DeptSolvev Process Div- Allied Ghent. & Dye Corp- Solvev, X. Y. or local Solvey sales branch oft. 15. I'sc of the Air-Chan Suit, 16mm sound. 30 min. color. Cost Reduction Section. Chamber Works. Organic Chemicals Dept- E. I. DuTont deXeroours & Co- Inc. (Perns Grove, X. J.) avail. both with magnetic sound tract & regular optical sound tract. 16. Breathing Apparatus, Fire Dept. Training Film, 16mm sound B&W, 30 min., Public Relations sect Lc Angeles Fire Dept., Los Angeles. Calif- also avail, as Xavy Train. Film 17. Breath of Life, 16mm sound, color. 10 tnin- Scott Avia. Corp., Lancaster, X. Y. 18. So. 2 Training Film, 16 sound B&W, 20 min- Scott distributors. 19. Damage Control, Oxygen Breathing Apparatus, MN-693IA, 16mm sound, B&\\. 22 min-, Xavv Train. Film, U. S. Xaval Train. Aids Center. E. Coast, 207 \Y 24th St, X. Y. 11, X. Y\ 20. Rescue Companies, 16xnm sound 30 min- by Warwick & Tompldn, Public Rela tions section, Los -Angeles Fire Dept- Los Angeles, Calit. 21. Serve Gas Casualties 6r Their Treatment, 16mm sound color, 30 tnin_, Stale CD Offices. or thru the Federal CD Admin, Battle Creek, Mich, on Fed. contribu tions prog, or thru W. B. Jacques, E. R. Squibb & Co., 745-5th Ave- New Y'ork. X. Y'. 22. Gas Obstacle Course, TF-14440, 16mm sound, B&W, 19 nun- 1W3 (Air Force) same source as 8. 23. The Effects of fVeaiker on the Travel of Smoke & Gas Clouds, TF-I-4666, 16mm sound, B&W, 21 nun- 1949. avail, same as 6. Chemical Industries A regular compressor and a standby com pressor were provided on the air line. Over a week-end. both compressors were out of sendee, so bottled nitrogen was manifolded into the line by a temporary* jumper con nection to maintain instrument air pressure. tor 10 days from a toxic exposure to phopene fumes, and was absent from work for about one month. The two other men suf fered no ill effects whatsoever. XO RESPIRATORY PROTECT!OX An employee, aware of tlie circumstances, was told to wear a filter-type mask. By habit, however, he entered the area and was found dead several minutes later due to nitrogen inhalation in the air-line respirator A chemist was decomposing a reaction mixture containing phosphorous oxychloride in a hood by pouring it over ice onto a four-liter beaker. While his back was turned, the reaction became violent and the he had worn instead of the filter-type mask. mixture overflowed onto the hood floor. A Breathing air systems, using an approved compressor or tank system, should lie closely supervised and used only for breathinr. Employees whose work takes them out of cornact (visual or audiable) with others should lie closely supervised. Human error caused this fatality. CARROX TETRACHLORIDE AGAIX fmall amount also spilled onto the laboratory floor, since be did not have a catchpan under the beaker. He directed his laboratory assistant to leave the room promptly, but stayed behind to throw some ice on the spill on the floor and open windows. He re-entered the labo ratory after 10 minutes, when the fumes had subsided considerably, and cleaned the spilled Bunker C oil leaks had sprayed oil over the wa11$ and ceiling of a small boiler room. Fearing the fire hazard which might result from using kerosene on the electrical equip ment, the plant engineer had four men use material off the floor. This required 30 minutes, during which period he inhaled some of the fumes, chiefly HCI. He did not use any respiratory protection, although it was available. a bucket of carl<m tetrachloride with a long-handled brush. Respirators of the proper type were pro vided and worn, litit due to a missing part and poor fitting on one mask, one oi the He did not notice any ill effects that day, other than eye and throat irritation, but he was hospitalized on the following day for broncltial and pulmonary congestion. He was m the hospital for four days. men became ill and was hospitalised three weeks with tyjncal carbon tetrachloride joiKinaur symptoms. * A vertical catalyst bed was being rodded out to remove solids. Dust and fumes from A properly adjusted respirator, a Jeff the solids being discharged at the bottom of toxic solvent (such as I.M-trichloroethane), the reactor were sufficient to cause coughing and ventilation--any combination of these and discomfort. to the operator, although measures would have prevailed this injury, spot ventilation was lieing used at the top h was also noted that the injured man oi the column. occasionally consumed alcoholic beverage.--- The operator continued to work out his a contra-indicated action in solvent areas. shift, but that night he had an attack of VHOSGESE A chemist suffered a major injury when phosgene gas containing dissolved HC1 es caped from a cylinder too fast for the cap acity of the hood. The chemist was wearing a Type X universal canister mask, but he noticed that his eyes were irritated when he nausea and vomitting, accompanied by per sistent coughing. Following a recurrence of the original attack, he was admitted to a hospital for four days. An ah* line respirator was readily avail able, although the magnitude of the d^st hazard was not fully appreciated at the time. took the mask off moments later in the fresh air. Two men who worked alongside him were wearing air-line respirators and did not smell Jihosgenc nor notice any eye or throat irritation. The chemist was hospitalized During the operation of a small scale reactor housed hi a barricade, it was nec essary to enter the barricaded area and with draw condensate every half-hour. This re moval consisted of opening a valve at the 25 1957 National Safety Congress bottom of a condenser to check for and re move any unconverted by-products. In per forming this operation it was necessary to discharge some vapors to insure complete withdrawal of the condensate. The injured had been doing this during his shift without using the air-line respi rator which was prescribed protection equip ment for this operation. In addition to this exposure, he had entered the barricade during the early part of the shift to make minor repairs to a leaky blower. The injured worked for several days with no apparent ill effects. While at home he developed a fever and shortness oi breath which was subsequently diagnosed as acute bronchial asthma. He was home for three days. In this case, the injured failed to obey written and verbal instructions to wear an air-line respirator, and the injured's shift leader failed to enforce this rule. Since then, all operators in this group have been reinstructed in the necessity for observing regulations regarding barricade entry, and have been informed that repeated violation of safety regulations 11123* constitute grounds for dismissal WRONG TYPE MASK An employee washing out a chlorine tank car passed out doe to insufficient oxygen. A fellow employee pm on a Type X uni versal canister gas mask and entered the car for rescue purposes. He, too, passed out and it was necessary to use self-con tained breathing apparatus to rescue both. Fortunately, both men recovered. 9 built up enough to activate a sprinkler head, which transmitted an A. D. T. alarm. Since very little smoke was visible external to the drying room (which was held at approx. 150F) the first firemen went in without any protection. They were quickly over come. Members of the rescue company followed closely behind using Type X universal can ister masks. These functioned well on the sixth floor outside the drying ream, but in side. one of these five men was overcome. The other four heeded the warning sign oi "overbreathing'* and retreated to fresh air before being overcome. These same men returned to the room after doiming selfcontained breathing apparatus. In all, 30 men were overcome in this multiple alarm fire--multiple only because all men from the first companies were overcome. All the firemen recovered. NO RESPIRATORY PROTECTION A chemist was preparing to use hydrogen sulfide for a determination and when the v*aive was opened, a leak developed because a washer did not seat properly. Before the employee could dose the valve, the hydrogen sulfide was ignited by the flame from a btmscn burner located in the same hood. In an attempt to dose valve, the employee re-entered the room, without wearing protective equipment, was overcome, and struck his head on the edge of a bench as he fell to the floor. He was res cued by another employee who was wearing a demand self-contained breathing appara tus. He was hospitalized for three months and as a result of this incident lost his sense of smell Fire was located in a drying-storage room of steel construction, measuring 6 feet x 50 feet x 30 feet dosed by an ablestos curtain at one end. There was no possibility of ventilating. The room was located on the sixth floor of a factory* and contained a large quantity oi ''wood flour** (pulverized saw dust), used hi casting ornaments, con tained in lOOjr bags. Fire was started by an electric motor in the rear-most portion of the room. The fire had smoldered for some time and this room was heavily loaded with smoke, and obviously a high CO and CO* content Alarm was sounded when the heat finally ANOTHER SOLVENT INCIDENT Two electricians, journeyman and appren tice, were working in a concrete pit-- four by six foot top opening and standing on the bottom, the ground level was in the proximity oi their eyes, nose and mouth. Repair of the small motor involved using a solvent an inhibited grade of 1,1.1-tridiloroethane. Approximately 10 minutes after ca tering the pit, the one electrician appeared to be swaying, somewhat in a stupor and somewhat incoherent. A combination of lifting and pushing forced the man out of the pit. The other electrician used the lad der in leaving the pit 26 Chemical Industries A few* minutes exposure to fresh air and the "overcome" electrician stood up and walked to the dispensary. Examination re vealed him to be coherent and no signs of narcosis. He rested for about half an hour and returned to his job--by this time the job in the pit was completed. A feu* pertinent facts are in order: sol vent was not spilled cm the floor of the pit, the "overcome** electrician had returned to work that morning after being off for sev eral day's due to a bronchial inflammation, and the other electrician never demonstrated or mentioned any ill effects. INERT CAS IX TANK CAR A tank cleaner entered a tank car (which had previously contained caustic soda) and started to wash it down with a hose with the bottom outlet open. After failing to reappear in a norma! time, investigation re vealed the man lying in the bottom of the car. Upon removal and attempts at resus citation, it was determined that he had died as a result of weak alkali solution having been taken into the respiratory tract This is strong evidence that the inert gas used to unload the car was a byproduct of chemical operations, low in oxygen and could have contained carbon dioxide, carbon monoxide, nitrogen and other constituents. Upon checking the air oxygen and 2000 ppm of reducing gases which would commonly* be reported as carbon monoxide. Inasmuch as the official coroner's report stated that the man fell to the bottom of the car apparently due to heat exhaustion, there was no significant publicity concerning this incident. Corrective measures have been takoi to avoid any recurrence. TANK JOB CLAIMS UFE A maintenance mechanic lost his life, and his assistant narrowly* escaped in tank inci dent. Repair work had been scheduled inside the tank to begin after lunch, and two men as signed to the job. The mechanic derided to look over the job about 11 '30 ajn. and went into the tank after sending his helper for certain supplies. The inert gas (which con tained essentially nitrogen with small per centages of CO and COj) supply to the tank had not been shut off, since the me chanic had not informed anyone of his entry. The mechanic was quickly overcome. His helper returned a few minutes later, shouted for help, then went into the tank to aid the first man who was unconscious. Before help arrived, the helper was also overcome, but both men were promptly re moved to fresh air. The helper was suc cessfully revived, but the mechanic could not !>e brought hack to life. Failure to follow established tank-entry procedures was the reason given for this fatality. INERT GAS Two men altered a kettle to repair an agitator, which is normally a two day job. On the first day nothing unusual happened. On the second day the men went into the kettle, worked for an hour, and came up tor a coffee break. When they re-entered kettle, they began to feel weak. They were actually too weak to climb out of the man hole after 15 minutes, but finally crawled out. They came to as they stepped out into the air. After investigation, it was discovered that one of the men had opened an inert gas line instead of an air line. Gose to the top of the kettle was a section for a hose line to be piped to outside the building. The hose was only half-way down into the kettle. The inert gas was heavier than air, when they* bent over to pick up tools, they would get inert gas until they* eventually were made ilL * * * An engineer went down to inspect a kettle. He began to feel sick and came out Upon investigation later they found the kettle had been "blown-out" with enert gas and did not follow through by removing the gas with proper air vertflation. (The engi neer recovered immediately upon leaving the kettle) A man went into a non-enameled kettle. The complete kettle was blanked off with exception of entrance. The kettle had been `blown-out" with inert gas. He was over come. It was necessary to resuscitate the man quite a while before he recovered. ILLUMINATING GAS IN TRENCH Two men were working in a series of three by seven by seven foot trenches dug along a 75-foot length of a street While tapping a high pressure illuminating gas main to install a jumper line into a low 27 J95T National Safety Congress pressure mam. a drill slipped and opened a valve in the tapping machine. Gas was re leased into the trench. One man immediately left the trench, hut the other was overcome. A laborer standing on the bank observed this, and imtnediaicly descended into the trench. He tied a roje around the waist of the unconscious man before he, too, was overcome. Meanwhile the foreman of the job put on an air-line respirator and went imo the trench to close the valve. By the time the two unconscious men were brought to the Surface by the foreman, one was sufficiently ill that inhalaters could not revive the laborer even after a half-hour of resuscitation. The other un conscious man was revived. The final score: three men treated at hospital for gas inhalation while one man was dead on arrival. MASK IMPROPERLY ADJUSTED A near fatality occurred when an oper ator went to tighten a chlorine line in the Waste Treatment Plant and the line disin tegrated, thus exposing him to a full blast of chlorine. He had his face mask an, but due to maladjustment, he was hospitalized for twenty-four hours. XARROW ESCAPE A plant protection officer entered man hole to inspect water valves, collapsed after about three minutes, was unconscious for three and one-half hours, revived by artifi cial respiration, li there had not been another officer watching and a truck with a rope on it nearby, this would likely have been a fatality. A six inch artificial gas main 30 feet away had broken and the gas had seeped into the hold. Xo respirator was worn. METHYL CHLORIDE A leak developed in the methyl chloride compressor which was being used to transfer methyl chloride from the drier through a tank to storage. The leak was first dis covered by a foreman who had heard the compressor pounding and who entered the area to investigate. Two men inhaled excessive quantities of methyl chloride. An operator entered the area with a filter type respirator, but left when he detected methyl chloride through his respirator. Shortly afterward he was observed staggering and shouting outside. He was wearing a dust respirator. Both met were given oxygen and sent to the dispensary. Each of the men had a pale white complexion with a bright red over tone. An examination of the compressor after the incident showed a crack along the base of the compressor housing. This was caused by liquid methyl chloride in the compressor. The tank had been full for three days and had been frosted over, indicating the presence of liquid. The incident was caused by attempting to transfer through the full tank. OXYGEX WASN'T THERE! During degreasing operations involving the use of Freon-113 (Trifluorotrichlorocthane). it appears that one operator fell into the lank while attempting to disengage the bas ket The other operator, without calling for help, immediately entered the tank to go to his assistance. Both men lost their lives due to suffocation in rite oxygen-defi cient atmosphere. In fire safety, we Itave long hammered at the point of calling assistance Wore tack ling any fire alone. The same point should be reiterated again and again in training l*rsonnel where the hazards of suffocation or entrapment exist. In many large chemi cal plants, personnel are oixoi widely spaced and telephones are not always readily avail able at all locations. In practically all plants, however, a fire alarm !>ox is located quite conveniently to all operating stations. Pull ing the fire alarm box summons trained assistance and supervision in a matter of seconds. Where feasible, employees should tie trained to use the nrc alarm box instinc tively to summon assistance before attempt ing on their own. In any case where hazard evaluation dis closes the possibility of suffocation or en trapment, personnel should lie thoroughly trained to overcome the instinctive reaction to go immediately to the victim's assistance and to summon help first by the fastest available means. HYDROGEX SULFIDE! One man suffocated and two escaped death when exposed to HsS. This accident was caused when a precipi tation tank overflowed and spilled add- 28 bearing liquor on the floor. Hie liquor the pit, his airline caught on the bottom of drained into a sump aeu the lead; station the handrail and impeded his exit. This and was then pumped into a reserve holding caused him to panic and he took off his tank. Later, pipes from a reserve sulfide mask. Hie foreman and the safety attendant holding tank were disconnected, allowing the running to his assistance; pulled him to contents to drain on the floor. safety as he collapsed. His workmate con The sulfide, during clean-up was washed tinued to work in the pit without any into the sump and then pumped into the trouble. same reserved holding tank. An immediate After being given artificial respiration reaction generated brge quantities of HsS, and an injection of coramine, the pipe-fitter fi!iing the area surrounding the tank. Una was removed to hospital where he recovered. ware of this, three emplovves entered the The apparatus which he had been wearing area. was subsequently found to be in good order, The first employee collapsed just as he passed the tank. The remaining two men walked a few* feet further: one collapsed and the other reached a window and called but it was unwise to compel him to work under circumstances of which he was obviouslv afraid. AMMONIA for help. Other members arrived and gave artificial respiration while the ambulance was summoned. On arrival at the hospital, the first employee was pronounced dead. One afternoon, while the engine-room foreman of an ice-cream factory* was stand ing near an oil separating unit, there was a report and ammonia liquid and gas issued Processing plants and laboratories in the from the sump. It was later found that the program contain the elements to produce not only gases like HjS but disastrous fires and explosions as well. These can occur from rubber seal between the sighting glass hous ing and the sump had "blown." The engine room was immediately evacuated, the fore an uncontrolled chemical process reaction man taking with him a canister respirator nr. as in this case, from improper mixture from a rack. cf two chemicals. Infrequently, storage of incompatible chemicals can be separated physically for safety, which was done here afterward. More reliably, however, the em ployees should be instructed fully in the adverse effects of chemical combinations jossible in the operation. Hie fire brigade was called and warning given to all employees in the factory*. As the concentration of gas was too high for the canister respirator, the foreman was unable to re-enter the engine room to reach the ammonia isolating valve. The gas spread rapidly through the factory* area and many ALIPHATIC HYDROCARBONS A pipe-niter, aged 26, was gassed by aliphatic hydrocarbon fumes in a pit 20 feet by 10 feet by 6 feet deep in an oil re finery while he and another man were in serting a blank in a pipeline which had been shut off. Both men were wearing breathing apparatus supplies with air from a handpump, a Y piece being used to supply the two sets of apparatus from a single pump. While working in the pit. the pipe fitter, who was apprehensive and difficult to reas sure, was seen to remove his mask. The safety attendant, who. with the foreman, was watching from ground level, replaced the mask and assured him that it was work ing properly. When the joint was opened, some liquid escaped owing to residual pres of the 100 employees, most of them womm, were affected. There was some degree of panic and some women were rescued from the canteen by firemen. Sixteen women employees and two firemen were admitted to hospital but only three persons were detained overnight. Seven of the women were sufficiently affected to require notification. Occupants of houses within a radius of 50 yards of the factory were also affected. The firm had already been advised to provide self-contained breathing apparatus and they were again advised to keep apparatus of this kind out side the engine room as well as the canister respirators. TWO FATAL ACCIDENTS WITH BENZENE VAPOR sure, and the pipefitter endeavored to come 2way, but was persuaded to return. Later, when he again attemirted to leave In one accident a laborer, aged 23, was fatally gassed and an ambulance room atten dant and a fireman were also gassed while 29 m ii ll 1957 National Safety Congress Chemical Industries attempting to rescue him. The foreman had given instructions for four of a series of 16 benzol tanks to be cleaned after they had been steamed oat, tested and declared free from gas. While the laborer with his workmate was preparing xo start work on a tank which had been steamed oat. he en quired about another tank which had not been steamed and was told they were not instructed to clean that tank. When the workmate returned after tetchmg a respirator and a lifeline he saw that a ladder and hose pipe had been lowered into the tmsteamed tank and that the laborer had unaccountably entered without a lifeline or respirator. After shouting for help he at tempted to enter the tank, at the bottom of which there was about 12 inches of liquid, but was forced to come out because of the fumes. During the rescue operations a fireman, who in his hurry entered the tank without a rrask, was gassed, as was the ambulance room attendant who had dormed a fresh-air mask and a lifeline but dislodged his face mask while in the tanks and lost conscious ness. The laborer was given artificial respi ration and oxygen but failed to recover. The other fatal case was a benrol house attendant aged 47, who was found lying prone and unconscious on the floor, which was saturated with benzol. He was im mediately dragged into the open air and artificial respiration was started at once, this being continued with the aid of a rocking stretcher, oxygen also being given. Despite this treatment, he was found to be dead on arrival in hospital \Yhoi the distillation temperature had been readied it was the attendant's dun- to reduce the steam sufficiently to allow distil lation to proceed in the normal manner. 1 this was not done, die crude motor spirit would boil rapidly and would eventually overflow on. to the floor. After the accident, the plant was found to be in order, and ft was assumed that the accident was due to the use of too much steam. CARBON DISULPHIDE Following the discovery of a leak at a rotary valve on an electric arc furnace used for the preparation of carbon bisulphide, the manager decided that breathing appara tus was necessary* while repairs were beh-g effected and he issued a penwt-to-work certificate accordingly. Without bring in structed to do so, a laborer climbed up a Udder to the top of the furnace. He was not wearing breathing apparatus and. being overcome by escaping gas. he fell to the ground about 10 f*ei below. After recovering consciousness he was able to walk to the ambulance room. FOUR CASES OF CHLORIDE POISONING In four cases in which only slight expo sure to chorine gas occurred, the effect? were stated to have been aggravated by the existence of a previous chest condition. One of these cases was a plant operator who inhaled a whiff of chlorine when adding hydrochloric acid to a reaction vessel under negative uressure, after having put in a slimy* of sodium chlorite. The doctor who treated him in hospital considered that the inhalation of a small amount of chlorine had "triggered off" an acute attack in a man subject to asthma. A process operator, aged 32, whose expo sure to chlorine from a leak in a plant for' the chlorination of dimethylacetal was slight, suffered from cough, breathlessness and pain in the riitsL The chest physician, who found a lesion in the left upper zone and kept him under observation at rest at home to as*es? tie activity of the tuberculosis lesion, thought the infection was a factor greater fi^n chlorine exposure in this case. A night watchman, aged 58, said to have had a previous chest condition, suffered from a sensation of choking, cough and respiratory tightness following a slight leak ,f chlorine from a control valve. The fc<ir*h case in this group was a fitter, igcd 57, who, with other men was cleaning an rir-cooler plant from which some water contacting four p.p.m. of chlorine was leakir;:. The other men were unaffected by the email amount of chlorine, but the fitter, who wri stated to be a heavy smoker, which raused him to cough continuously, became unconscious and suffered irom lachrymation and cocgh. IMPROPER VENTILATION X laboratory technician was cleaning a vessel with a mixture of hydrochloric and nitric adds. The work was being done at a jink in front of an open window. How ever, there was not sufficient ventilation to prevent the worker from inhaling fumes to make him sick to his stomach. The proper type Canister Respirator was available on the lower floor but the person was not familiar with its use. SO RESPIRATORY protection Several specific instances are known where personnel should have worn protective equip ment and did not although it was available and the specific personnel were familiar I with use. For the most pan these instances involved professional grade personnel of the "difficult personality" category engaged in Research and Development. Injuries were j in all of these cases from volatile vesicants, 5 and though injuries were serious enough to have resulted in lost time, there was, in fact, no lost time. In one instance the employee was con vinced to use recommended safety proce dures by a combination of greatly increased supervisory pressure and alarmist industrial hygiene propaganda. In another instance such stresses produced no apparent effect respiratory problems We have had people injured while they were wearing respiratory equipment and also we have than injured by not wearing them m en though they were available. Some of the latter are the "Smoke Eater" type who think they can get along without the stand-by equipment A basic problem with any respiratory protective equipment is knowing the limita tions of a particular device. Actually, the popularity of the self-contained breathing apparatus can be attributed to the fact that its limitations are far Jess than any of those that depend on chemicals for air purification. In addition, the operator does not have to be concerned in knowing whether there is sufficient oxygen in the air. In one particular process we were con fronted w*ith a cumber of stages in w*hich reactants were more or less open to the atmosphere. In spite of a number of spot ventilators there was a prevalence of noxious odors, most free chlorine. Chlorine is considered here for its nui sance and noxious characteristics rather than for its toxicity. Even small amounts have a definite odor and they usually cause an operator to get out of the contaminated area. This Utter inridently provided cause for as additional problem and usually ended in a lost time injury. Many times the in dividual would go outride for fresh air where it was too cold for his condition. He would catch cold and would come near to developing into pneumonia. During the time this particular process was being developed, operators got used to the chlorine type odor. At this same time the self-contained breathing apparatus was not the popular item it is today. A chemical cartridge respirator was what the)* gener ally carried draped about their neck. Prob ably many times the trouble was located and the mask removed after the contami nated area was tinder control without the operators* having an exposure. A number of times though, the capacity of the cartridge was unknowingly depleted by prior uses. Then again, the general con tamination would instill in the operator the idea that bis mask was O.K. when it really wasn't. The operator would then prolong his trip beyond limits and have an exposure. To sum up then an operator: a. would not know the conditions of his mask because he was generally conditioned to the contaminant. b. would not know the remaining capa city of the mask. c. would realize that the mask was not working but would remain in the area thinking he could get by or hold his breath a moment longer in order to complete the job. The second pan of the problem refers to the people that do not use the equipment that is available. These are the "Smoke Eaters'* or the ones that think they can chance it Even today with the self-con tained breathing apparatus available, this practice continues. I witnessed an entry to a contaminated area (FH fog). This particular entry was made for no good reason at all. Two men were putting their self-contained breathing apparatus on and this fellow decided to go in with a handkerchief over his nose. It turned out that the men wearing self-contained breath ing apparatus made the necessary emergency shutdown, ventilators soon decontaminated the area, and normal entry could be made. 30 31 . cJ/ ' .-/* v- / a 1957 National Safety Congress SOAP DUST Our operation is essentially a soap manu facturing plant and the air in our factory* is frequently contaminated tcith soap dust from detergents and dust arising from fine woodfiour and contmeaL We issue our cm* pierces a dost mask (not Bureau of Mines ap proved).The filter element consists of a honey comb construction of whipped foam latex. This device does a modest job of filtering, however, we have never been complete1** satisfied. Despite the fact that we have issued masks to all personnel about half ci our personnel prefer to use an ordinary handkerchief wrapped about their face which appears to do a satisfactory job without the unpleasantness of the dust mask,A OUTLINE SOI SELECTING K$ftfcTO*T rtUILCIItE OEflCES '`-0ft>erwpi-- Toic CdRtlBtBICl Seff-tontoiaed Hssc raasfc IflitMdiatrfjr dnfcross ts life Sctl-csntsincd Hose ***** breettuef wife Ccsceas i "i Gss Air>!mt ' Gascon ad pcrticeUt* NOT iaMweisteir dcaicroos to life I Oast. rant. or tone respirator -!- T I Hsu susft Cfecmcal cartridfe Ah-irm rcss*rotor Abrosfec bfestisf respirator Immediately descents te life i------------I----------------1 Self-conUiaed Hose amt Cu rank fcruferox citk wife Mover special filter NOT immediatefe desceroos to life Arr*lrae Hose "*** respirator Tittwct cartridi* taprrotot special fitter "Reprinted from Burtso of Uiroi tnbraetioa Cirouter 7792.' 32 LABORATORY AND PILOT PLANT SAFETY (A Symposium) LABORATORY BARRICADING OF HIGH PRESSURE AND EXTRA HAZARDOUS REACTIONS by GODFREY J. MOLL chemical engineer, CIBA Pharmaceutical Products, Inc* 5umrnH, N. J. Safety engineers are often called on to formulate or approve plans for laboratories in wltich high pressure or extra hazardous reactions will be safely operated. In these designs tle protective shield or barricade is the only fixed piece of safety equipment which will remain operable 100 per cent of the time. Equipment, instrumentation, and afetv devices are all apt to iail at any time regardless of maintenance and inspection. The judgement of the best-trained operating jersormel need only be wrong once. The barricade may be considered as the primary safety device. High pressure and extra hazardous re search projects are being carried out in unbarrieaded laboratories in many univer sities and at same industrial research centers in the United States. Workers at these in stallations will point with pride at their per fect safety record, but tomorrow* might yield their first and last accident The manage ment of CIBA Pharmaceutical Products Inc of Summit X. J.. has recognized the risk involved in not hardending high pressure reactions. Our high pressure laboratory* w*as con structed in a built-up area presenting the problem of not only protecting the operating personnel but also the personnel of adjacent ioildmgs from the effects of missiles and shock waves. A suitable barricade was con structed of 16-inch reinforced concrete with a reflector wall of similar construction eight feet from the frangible wall. Further pro tection was provided by hanging one-half inch wire rope blast mats between the build ing and the reflector wall, which would operate on the ballistic pendulum theory in stopping missiles and dissipating shock waves. This is but one approach to the problem of barricading. The question often arises as to what should be considered hazardous enough to warrant the expense of barricading. Some authors fed that when equipment is in stalled to handle inflammable materials at pressures greater than 500 psi the use of some form of barricade should be consid ered. When research at high gas pressures or work on known explosives is conducted tlie protection of personnel and other facili ties with an adequate barricade must be considered. In small-scale flow experiments where the amount of material in process is small, it is common to use pressures as high as several thousand pounds without special barricades. Once it las been decided to build a barri cade there are still many questions to be answered. The two most important as far as the barricade is concerned are the mate rials of construction and their thickness. MUST KNOW MISSILE If we knew the velocity, weigh: and shape of the missile and the maximum force expected from an explosion, we could de sign a barricade using a minimum wall thickness. Barricades must be designed to prevent penetration by large missiles at low* velocity*, such as reactor heads, and also small missiles at high velocity, such as tub ing, nuts or other small fittings. Penetra tion is dependent upon the velocity of the missile at impact, the physical properties of the missile, and the characteristic of the material used to construct the harrier. The speed of sound has been suggested as a velocity*, as most objects when propelled through air decrease in velocity to the speed of sound. If missiles of higher velocity are expected, the modified Petry equation for penetration can still be used to calculate a 33