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Safe Pracf/ees Pamphlet No. 7? Handling Chlorine Published by National Safety Council 425 North Michigan Avenue, Chicago 11 General 1. The hazards involved in the use and handling of chlorine are moderate if certain precautions are observed. The comparatively few accidents caused by it have been in most instances due to a lack of knowledge of the properties of chlorine or to failure to follow recog nized safety precautions. Particular at tention is called to "Interstate Com merce Commission Regulations for the Transportation by Rail of Explosives This pamphlet is one of a series of more than 150 Safe Practices and Health Practices Pamphlets issued by the Na tional Safety Council. As a compilation of experience from many sources, it should not be assumed to include every acceptable procedure in the field covered. Neither is it intended that the suggestions presented herein shall in any way super sede American Standard safety codes; federal laws; insurance requirements; state laws, rules and regulations; or municipal ordinances. Additional copies of this pamphlet are available. Member price, 45 cents each. Quantity jnd non member prices on request. increase because of the corrosive action of chlorine in air, which always con tains some moisture. Additional infor mation on the properties of chlorine will be found in such publications as "Lunge's Textbook of Inorganic Chem istry," "Tables of the Smithsonian Insti tute," "Mellor's Treatise on Organic and Theoretical Chemistry," "International Labor Office Brochure N'o. 34," and "Thorp's Dictionary of Applied Chem istry." and Other Dangerous Articles in Freight, Express and Baggage Services," effective October 1, 1930, and supplements there to, published as Pamphlet No. 9 by the Bureau of Explosives. -28.5 degrees Fahrenheit has a gage pressure which is expressed in Fig ure 1. Liquid chlorine is an amber colored, oily fluid, about one and Physiological Effects 4. Physiologically, chlorine is a skin, mucous membrane and respiratory ir ritant. Exposure of the body to two 2. Large quantities of chlorine are used in the preparation of bleaching agents, fire extinguishing fluids, solvents, antiseptics, anaesthetics, and fumigants; in the purification of drinking water; and in connection with the disposal of sewage and industrial waste. one-half times as heavy as water. At temperatures above -28.5 degrees, the liquid gasifies at atmospheric pres sure. Chlorine as a gas is of a green ish-yellow color with a characteristic suffocating odor, and is about two and one-half times as heavy as air. Neither the gas nor the liquid is flammable or per cent of chlorine in the air for ten to twenty minutes will cause marked irritation and blistering of the exposed areas. In sufficiently high concentration the gas may cause death. (See Table A.) When death results, it is generally caused by smothering or stifling; that is, by inability to breathe and by the Properties explosive in itself. A small gas leak spasmodic closures of the bronchial in a chlorine container will gradually tubes. With exposure to . chlorine gas 3. Chlorine is there is at first gen not found free in na eral excitement as ture. Commercially indicated by rest it is produced al lessness, urination, most entirely by irritation of the eyes electrolysis of so and throat, sneez dium chloride or ing, copious saliva potassium chloride. tion, retching and As an article of vomiting. This is fol commerce it is lowed by difficult or shipped as a liquid labored respiration. under pressure in Respiratory distress steel containers which must conform increases until even tually death may to Interstate Com merce Commission regulations. The liq O 40 &0 '20 'fcti 200 a40 HO Jto J*4 400 440 *90 (jAGd //V L3S>. PC* 4XP /AS. occur from apparent SU3 00 asphyxiation. Medi cal authorities claim uid in approved containers at tem peratures above Figure t. Curve showing gage pressures of chlorine at different temperatures. The pressure of chlorine in containers increases with a rise in temperature. It is. therefore, important chat the containers be kept away from excessive heat. that the effect of chlorine on the skin and mucous mem- (Copyright, 1926, 1920, 1926, National Safety Council. AH rights reserved. Printed in U-S-A.) R$V 0005969 2--S.P.P. 71 . SAFE PRACTICES PAMPHLET NO. 71 Table A Physiological Response to Various Concentrations of Chlorine Gas Effect Parts of Chlorine Gas Per Million Parts of Air Minimum detectable odor .................................................................................... 3.5 Minimum amount required to cause irritation of the throat........... 15.1 Minimum amount required to cause coughing............................-......... 30.2 Minimum amount required to produce slight symptoms of poisoning after several hours of exposure..................................... 1.0 Maximum amount that can be breathed for one hour without serious effects ................................................................................. 4.0 Amount dangerous in 30 minutes to one hour .....................................40-60 Amount likely to be fatal after a few deep breaths..................... 1000 NOTF' The above data nave been taken from United States Bureau o( Mines Technical Paper 248. "Gas Masks tor Gases Met in Fighting Fires." branes is caused by its reaction with by no else. He should be familiar with the moisture present to form hydro the accompanying instructions and chloric acid. They also claim chlorine trained to hold his breath and to put is nearly 20 times as toxic as hydro the mask on quickly and properly. It chloric acid, and because of its rela is also desirable to have available for tively low solubility, its locus of action such a person rubber gloves and a suit in the respiratory tract is much more of rubber or other impervious material. extensive than that of hydrochloric acid. When in use, the suit should be securely 5. In any atmosphere containing chlorine, short, shallow breathing should be used. Chlorine produces no cumula tive effects, and complete recovery from fastened about the neck and at the wrists and ankles. Periodic inspections and careful maintenance of gloves, suits and approved gas masks are essential. mild exposure usually occurs. Since chlorine is especially irritating to per Handling Containers sons afflicted with asthma and certain types of chronic bronchitis, such persons particularly should avoid exposure to the gas. 8. Every container holding chlorine, either gas or liquid, presents a hazard, and it must be handled with care. (See Safe Practices Pamphlet No. 95, "Com Protection pressed Gases.") The word "container" as used in this paragraph applies to all 6. The greatest danger from chlorine containers of one ton capacity or less. occurs where there is a sudden exposure The Chlorine Institute recommends that to a concentration such as may occur the following rules be posted in con from a broken valve or pipe. The spicuous places: danger is particularly acute from chlo rine in a liquid state, when it is under pressure and vaporizes readily. a. Neither drop containers nor permit them to strike each other violently. Ij. Never use g lifting magnet or a 7. It is imperative that some form of protection be provided for emergen cies. Several types of gas masks ap sling (rope or chain) when handling containers. (Note: One National Safety Council member states, "Hoisting is to be avoided as much proved by tne United States Bureau of as practical, low rubber tired or jack Mines, ana citable for use in atmos pheres containing not more than two per cent of chlorine gas, are available.jA sufficient number of such gas masks* trucks being preferable. Where hoisting is necessary, safe lifting clamps are preferable to ropes. The use of cables or chains as slings is very dangerous.") should be on hand, located at readily c. Before returning empty chlorine accessible points outside of the area likely to be affected in case of an acci dent. The instructions accompanying a nicsk, concerning its care and use, containers, close their valves and test for chlorine leaks at the valve outlets by applying an ammonia water soaked rag attached to the end of a stick of considerable length. should be followed implicitly. Every The formation of a white smokelike one who is in danger of being accidental ly exposed to high concentrations of chlorine should be provided with an in dividual gas mask, preferably to be used cloud will result if there is any chlorine gas leakage. If no leakage is indicated, apply cap nuts to valve outlets and attach valve protection housings or caps securely in their proper places. These fittings should always be kept in place except when the containers are being emptied. d. Containers must not be refilled ex cept with the consent of the owner and then only in accordance with the Interstate Commerce Commis sion regulations. c. Never under any circumstances mix gases in a container: it is not only dangerous, but contrary to Inter state Commerce Commission regu lations. f. It is illegal to remove or change the numbers or marks stamped on containers without written authority from the Bureau of Explosives, 30 Vesey Street, New York City. g. Never use containers as rollers, sup ports, or for any purpose other than to contain chlorine. h. Never tamper with the safety de vices in the valves of cylinders. i. Open container valves slowly. The use of large wrenches or pipe wrenches may damage the valves. j. Make sure that the threads on regu lators and unions are the same as those on the container valve out lets. Never force connections that do not fit. The outlet threads are not standard threads. k. Containers or valves should never be repaired or altered by the con sumer: the owner only should under take this work. It is illegal to ship Figure 2. A low-wheel truck such as this provides a safe way of moving a cylinder from place 10 place when it is necessary to draw off small quantities of chlorine gas at different places. RSV 0005970 HANDLING CHLORINE 5.P.P. 71--3 a defective or leaking Container- Telephone the owner or nearest ( chlorine plant for assistance in an emergency. I. All containers should be protected against excessive rise of tempera ture. Containers may be stored in the open, but in such cases should be protected against extremes of weather. During winter, containers stored in the open should be pro tected against accumulations of ice anil snow. In summer, containers stored in the open should be screened against continuous direct rays of the sun in desert or other localities where extreme tempera tures may prevail. in. Never store containers near highly flammable substances such as oil, gasoline or waste, Council Note: These canister masks should be located outside the ap unloading should be devoted solely to this purpose. n. When practicable, do not store con tainers where they arc exposed to continuous dampness. o. Store full anti empty containers in different places to avoid confusion in handling them. (National Safety Council Note: It is also good prac tice either to lag the empties or to mark them with chalk.) p. Do not store containers near ele parent area of contamination so that in the event of the escape of chlo rine gas, a person can get to the masks. Gas masks of the canister type do not supply oxygen and should not be used in atmospheres where the oxygen content is less than 16 per cent. In case of doubt as to the amount of oxygen in an atmosphere, it is best to use a fresh air hose mask. c. When a chlorine tank is spotted on a siding for unloading, brakes must be set and wheels blocked. Caution signs must be so placed on the track or car as to give necessary warning to persons approaching car from open end or ends of siding and must be left up until alter car is unloaded and disconnected. Signs must he of metal, at least 12 by 15 inches in size and bear the words, "STOP vators or gangways or in locations r. If it becomes necessary to warm --Tank Car Connected," or "STOP where heavy objects may fail or a container, use great care because --Men at Work," the word "STOP" f strike on them. V of the low fusion point (157 degrees Fahrenheit) of the safety plugs in being in letters at least 4 indies high and the other words in letters q. Chlorine canister gas masks of a type approved by the United States Bureau of Mines should be always the valves of the cylinders and in the heads of the ton containers. at least 2 inches high. The tetter? must be white on a blue background. readily available at places where The valves should never be heated. d. Tank car outlet valves should be chlorine is used. (National Safety s. Containers should be stored in an upright position, thus keeping the liquid away from the valve- (One ton containers are usually stored horizontally because of the difficulty kept closed when operator of chlo rine line is not on duty and the pipe line beyond this valve should not be left full of liquid chlorine during shutdown periods. of handling them in an upright posi e. When tank cars are located on a tion.) dead end siding, the cars should be t. Reducing valves and gages designed only for chlorine can lie used on containers for this exacting service. Consult the container owner about such matters protected on the switch cm! by a derail. If on an open siding, de rails should he provided at both ends. Keys for the derails should be in charge of the operator of the chlorine line. f. Unloading of single unit cb'or-.nc Handling Tank Cars tank cars should be done through a coil allowing a moderate flexibility Coil may be of heavy copper tubing 9. Special precautions should be ob served in handling tank cars of liquid chlorine. The Chlorine Institute recom mends the following: for 500 pounds per square inch working pressure- A coil, however, should not be depended upon as a safety factor in case of a bump. Derails, flags, and lanterns should lie used. Unloading, connecting, and a. Cars must be unloaded only on a disconnecting operations should be properly protected private track of performed only in well lighted the consumer, or in the case of places by reliable persons who are multiple unit cars where no private properly instructed and marie re track is available, in accordance with sponsible for operations and who \ Interstate Commerce Commission arc equipped with chlorine gas Courtesy Pennsylvania Salt Co. regulations. masks. Figure 3. Use only the proper tools for opening cylinder valves. Never force a valve. !>. When possible, switch tracks on which chlorine cars are placed for g. It is illegal to ship a defective or leaking chlorine tank car. If a tank RSV 0005971 A--S.P.P. 71 SAFE PRACTICES PAMPHLET NO. 71 car is in' bad order or if there is an accident, telephone the car owner or the nearest chlorine plant for as sistance. The telephone numbers and residence addresses of the near est chlorine plant organization mem bers should be posted in the office of the person in charge of the han dling of chlorine in the plant of the user, in the first-aid room, and in the office of the manager. h. Consult car owner about return of multiple unit tank cars. It is illegal to return the ton containers of one ownership on the underframe of an other ownership. Emergency Measures 10. Persons handling chiorine should be protected from leaky containers. For this purpose the Bureau of Explosives recommends that at each unloading sta tion there be provided chlorine gas masks of a design approved, by the United States Bureau of Mines, and that employees at each unloading station be instructed in the use of the masks, and also instructed as follows: (A) How to Handle Chlorine Leaks (a) Keep on the windward side of the leak. (Ij) If leakage is extensive, promptly warn all persons in the path of the fumes to move to a safer location, preferably to an elevation consid erably above unloading location. (c) Use hose to spray water freely under slight pressure on the escap ing liquid. This forms chlorine hydrate, from which the evapora tion of gas is slow. Caustic soda dissolved in water adds to its effec tiveness as an absorbent of chlo rine gas. (d) If lank is punctured above the liquid, the gas will escape, and as water applied to gas leakage is not effective, the tank should be turned over to bring point of leak age below the level of the liquid. Leakage of liquid can then be re tarded by the use of water. (e) If water is not immediately avail able, dig a trench to draw off the liquid to a lower spot, the object being to reduce the area of the surface of liquid from which evapo ration takes place. Loose earth; cement; lime, either fresh or slaked; and textiles, wet or dry, especially bagging and felt, thrown on the liquid at once will act as an absorbent or blanket and effec tively retard evaporation. If avail able, dry ice (solid carbon dioxide) packed as well as possible around the leaking container will so re duce the pressure that the leak will be greatly reduced. Figure 5. A portable combination derail, warning target and lantern suitable for pro tecting chlorine container cars against acci dental shifting while being unloaded. (f) When attempting to plug a leak in any manner, hands and body should be protected against the escaping chlorine by the use of thick, loose-fitting gloves and a long apron of leather or similar flexible, non-porous material. (g) In a severe fire, leakage should not be serious as the gas will be carried upward and dissipated with the products of combustion, If the container is not leaking, every effort should he made to extin guish the fire- (Ii) When a pond or larger body of water is available nearby, the leak ing tank should be entirely sub merged, otherwise, if possible, tank should be moved to a point where escaping vapor will be carried by the wind away from the railroad yard or right-of-way and adjacent occupied buildings. (B) How to Use Gas Masks (a) Persons delegated to use gas masks should practice regularly with them in order to become pro ficient in the operation of putting them on as quickly as possible in case of emergency, and also to be come accustomed to breathing through them, as more power is required to draw air through the canister than is required in breath ing under normal conditions. Hence, practice will aid materially in overcoming this natural handicap to the activities which the wearer has to perform while using the mask. When removing paper disk seal from canister for practice pur poses, care must be taken not to injure the disk as it must be se curely replaced immediately after the practice drill. (b) Mask should be adjusted strictly in accordance with instructions furnished by the manufacturer. (c) Walk up and down in an un affected area to see that mask is working satisfactorily, and then walk slowly from the windward side, if possible, into the affected area. (d) Under no circumstances should a person equipped with mask run or become unduly excited so as to cause quick breathing, as under these conditions it will be more difficult to inhale through the re sistance of the canister. (e) At least two men should always be equipped with masks at the same time, the second man hold ing himself in position to be of assistance to the first man in case of emergency, such as mask being torn, development of leak, or in jury due to tripping or being struck by some fajling object. (C) Treatment of a Person Affected by Chlorine Gas (a) Remove at once to open air and away from all gas fumes. (b) Place patient flat on back with head slightly elevated. (National Safety Council Note: Patient should be kept warm. Do not exercise or excite him.) (c) If patient is not unconscious, give /l i teaspoonful essence of pepper mint or a moderace dose of bromoseltzer or a moderate stimulant NEVER ADMINISTER MILK. (National Safety Council Note: The use of milk or cream is not recommended because they usually curdle in tiie stomach and cause vomiting which adds to tlie dis comfort of the patient.) (d) The person affected should resist as much as possible the impulse to cough. (c) A physician should always be called- (f) If patient is unconscious and not breathing, use the prone pressure method of producing artificial res piration. A CKNO WLEDGMENT This pamphlet was reviewed by Floyd A. VanAtta, Industrial Hygienist, Indus trial Department, National Safety Coun cil. It has been reviewed by the members of the National Safety Council Safe Practices Conference Committee, the Chlorine Institute and the Bureau of Explosives. Rep. IM--351--WHP 0005972