SAFETY in the CHEMICAL LABORATORY EDWIN C . BUXBAUM, B.A., A.R.P.S. 1811 East Wood Place, Milwaukee, Wisconsin
Care and safety are increasingly necessary in the modern chemistry. Modern chemistry requires new safety rules. The trained chemist presents a n individual safety problem. Chemical accidents are avoidable. Fire and the commonest causes are discussed. Fire extinguishers of various types and their nses. Chemical burns of different kinds. Goggles end their uses. Handling of poisonous mateyials. Gas cylinders and their hazerds. Accidents from glassware. Accidents due to vacuum. Explosive reactions and accidents. Known dangerous reactants and chemical knowledge prevent accidents.
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N THE days of the alchemists, the elements were few in number. Fire, air, earth, and water were the four basic constituents of all matter. Today, the chemist does not work with four but with more than twice forty. Innumerable combinations of these elements form the hundreds of thousands of compounds known t o the research chemist today. In the pursuit of knowledge of these multitudinous combinations of matter, the chemist has had to take infinite care. Not only care in his work for purity of his preparations, care in the theoretical building up of his syntheses, or care in the study of the thousands of mysterious reactions, but care in the safeguarding of his health and person. As the chemical sciences grew more complex, the need for safety in handling the materials of chemistry grew more necessitous. With the growth of the new chemistry came the safeguards for the new risks which were to be involved. r Electrolytic chemistry with its electrical paraphernalia demanded new protection against electricity and heat.
In this experiment. the chemist is using a De Khotinskv thermostat for ternoerature control. The liquid bath may be water or oils of some kind depending upon the temperature which must be reached ~
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New compounds were found to be exceedingly poisonous and new antidotes had to be found. The chemistry of explosives emphasized the need for care. The World War with its gases and death-dealing fumes of all kinds gave an impetus to safety in chemistry and in the laboratory where all chemistry and chemical discovery has its conception. To impress a professional man such as a chemist with the fundamental ideas of safety necessary to his profession is somewhat of a harder task than that of instructing a laborer or worker in simpler lines of work. The professional man should of course be fully cognizant of any dangers that he may run. He should know the dangers of any work that he does and, usually, he does. I t is human nature to treat with contempt and disregard, however, materials which are in themselves exceedingly dangerous but which under ordinary conditions are handled safely without accident. It is exactly a t the moment when such a state of mind is in possession of the chemist that the greatest number of accidents occur. The laborer can be warned that he will be discharged if he violates any safety rule, but the chemist who knows more about his chemical compounds than anyone else and. treats them carelessly must be reminded. Accidents in the chemical laboratory are as avoidable a s any other accidents are. The few times when accidents are due to wholly unforeseen causes which might be classified as "acts of G o d are no more numerous than in any other profession. The accidents that occur in chemical laboratories are, almost without exception, avoidable with care. The layman's conception of the laboratory as a place where mysterious solu-
AN EMERGENCYSHOWER SEOULDALWAYSBE HANDY IN ANYLARORATORY WHERE SMALL-SCALEOPERATIONS ARE TRIEDOur Ahovethe showertotheleft. note the lamp, which is never allowed to be out, and the form of the volume of water which is concentrated on the head of any person below it and covers the body thoroughly with a heavy volume of water.
heat inflammable liquids in open containers such as beakers. Every chemical laboratory should have certain safeguards against fire. Fires of a chemical nature are peculiarly difficult to extinguish sometimes. The solvent fire may be extinguished with a common acidsoda or Foamite extinguisher of sufficient size. Usually, a small carbon tetrachloride extinguisher is used. While quite effective for small fires, these are sometimes dangerous. Large laboratory fires should be GOGGLESPLAY AN IMPORTANT PART IN THE CHEMICAL extinguished by other means. It is well known that LABORATORY carbon tetrachloride forms poisonous fumes of phosThey must have lenses strong enough to resist flying shatgene in small amounts when sprayed into a fire. While tered glass and must not permit acid solutions to enter. the gas is not formed in sufficient amount to cause In addition, they must be comfortable. death, it is certainly of an unpleasant and possibly tions and mixtures automatically blow up, take fire, or dangerous nature. The best and simplest aid to small fires on chemical explode is as erroneous as the old idea of the alchemists apparatus is the rag. A plain rag of any kind shouId with their four elements. be kept handy wheu heating any liquid which might Nevertheless, many of the accidents in the laboratory are traceable to fire. Fire is always a problem for take fire. The rag can he pushed down on the piece safety in the chemical laboratoty and especially in the of apparatus to exclude air, which will put out any small
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SARETY WOOLEN
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BLANKETS 1
SMALLFIRE EXTINGUISNERS OF
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CARBON TETRACHLORIDE TYPESHOULD BE CONVENIENTLY IN TRE CHEMICAL LABOPLACED RATORY
kith a Cellophane window.
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organic chemical laboratory where many inflammable solvents are used. Heating inflammable liquids like benzol, naphtha, gasolene, ether, carbon disulfide, and many others should be done without the aid of a flame a t all, if possible. If the temperature required is below a hundred degrees, a water bath or brine bath may be used. Such a bath can be heat$ electrically with a heating unit controlled by a thermostat of the De Khotinsky type. If the temperatureneeded is higher, an oil bath with electrical control may be used. Glass flasks, even wheu made of Pyrex, should never be heated in a direct flame. When agitating a solution of an inflammable liquid, great care should be taken to see that the agitation is not interrupted so that no overheating, with consequent boiling over, will result. Almost invariably, when a flask containing inflammable liquids is heated with a direct flame and the agitator stops for some reason, a fire will take place when agitation starts again due to overboiling of the superheated liquid. With an electrically heated fluid bath, this danger is overcome. Sometimes, test-tubes containing inflammable liquids are carelessly heated and result in fires due to vapors boiling over the side of the tube. If it is necessary to heat liauids of this nature in such a manner.. i- t should be done carefully over a small, cool flame. Never
They should be regularly inspected but should not be depended upon for large fires. Other extinguishers of the acid-soda or the Foamite type should be available.
-, fire instantaneously. In laboratories where smallscale plant experiments are being tried out, the regulation emergency shower should be within easy reach. Next to burns from fire, burns from alkalies, acids, and corrosive liquids, like phenol are most numerous. Acid and alkali burns require immediate flushing with water and medical attention. Burns from phenol must be washed off with alcohol immediately and then given expert attention. Other corrosive liquids require individual treatment for their immediate removal.
THETWOTYPESOF GLOVES MOSTCOMMONLY USEDIN THE CHEMICAL LABORATORY Those on the left are of leather and are used for handling hot beakers, fusion pots, or any other piece of hot apparatus. Those an the right are of the rubber gauntlet type and are used for handling corrosive liquids as acid.
No acid burn should ever be neutralized in the college freshman manner with alkalies, or vice versa for alkali burns. Water is the only first antidote. Other burns of more complicated nature, as those from bromine, require medical attention a t once. Self-medication should never be resorted to and all cases of chemical bums of any nature should be treated by competent physicians. Every laboratory should have a woolen blanket available for fires in which the clothing of the chemist burns. These blankets should be so Co~REcT TO pILLA folded that one jerk from PIPET their receptacle will entirely N~~~~use the mouth to unfold them. They should suck up corrosive or dan- be pure wool and heavy g e m s liquids. This can be enough and large very easily done with a vacuum line and a piece of tawrap an adult. rubber tubing. Goggles of various kinds are a prime necessity for the chemist in his experiments. They protect his eyes from acids, alkalies, poisons, and shattering glass apparatus. No experiment that involves any hazard of explosion or fire should be performed without goggles. The structure of goggles for the chemical worker should be such that the glass will withstand shattered glassware and the goggles should fit the face snugly. If there are any holes on the sides, they should be very small so that they would stop any small drops of acid from entering. The goggles should be well built and comfortable so that they may be worn for reasonably long periods without discomfort. Assistants and helpers who wash dishes with acids as cleansing agents should always we;r goggles and doves. If acids are handled, rubber gloves of the gauntlet type of heavy rubber should be worn. They should not be patched when they develop holes but should be discarded immediately. For handling hot beakers, oil baths, and flasks, leather gloves, which are non-conducting of heat, should be employed and not rubber gloves of any kind. -
Next to fires, accidents from poisonous materials, fumes, and gases, and accidents from mishandling corrosive chemicals are most numerous. Whenever a poisonous gas is generated, it should be absorbed in a container or trap of some kind containing a neutralizing chemical. If this is not possible, it should be drawn off with vacuum under a hood. Sometimes, a vacuum may be used to draw off poisonous fumes by inserting the end of a rubber tube in the outlet of the apparatus. A common cause of mouth burns is the use of the mouth to fill a pipet. In handling any dangerous
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AND ALL CORAcros, ALKALIES, nosrvE LIQUIDSSHOULD BE ENCLOSED IN
BOTTLESWHICHARE
PROTECTED BY METAL CYLINDERS
IN CASE OF BREAKAGE The liquids are blown over by air pressure which is regulated by a pop valve to a maximum pressure of two pounds.
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GASES,AS AMMONIA, HPDROGES, AND
CHLO-
BE TRANSPORTED ON A SPECIAL TRUCK RINE, SHOULD They are thus kept in an upright position and can be clamped on the truck.
liquid, it is best to apply vacuum to fill the pipet with the aid of a piece of rubber tubing connected to a vacuum line. Cvlinders of eases like chlorine and ammonia should be transported on small carts especially built for them in which the cylinder is securely contained. If this is impracticable, small cylinders, about a foot high, of the gas used may be obtained. They are easier to handle and can be placed upon a small balance to determine the amount used during a reaction. If extremely poisonous gases such as phosgene are used, a special hut with ventilation outside should be built adjacent to the laboratory. All experiments with the
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poisonous gas can be performed in this hut. Before entering, the door should be left open for two minutes to allow any traces of residual gas t o escape. I n t h e handling of glassware, only that glassware should be used which is strong and resistant to heat and sudden cold. Such a glass is pyrex which is used almost universally in the laboratory today. Soft glass for tubing and rods should be handled with sharp triangular files. All cutting should be done with
Both hands under the rim of the beaker prevent undue strain and breaking. Many cuts are avoided in the laboratory by proper use of glass apparatus.
the aid of a towel or rag to protect the hand. Especially is this necessary when putting a piece of glass tubing through a stopper, either cork or rubber. Many chemists suffer painful cuts through neglect of this rule about which every college freshman knows. It is especially important from the safety .point of view for the chemist to protect himself from the accidents due to vacuums. Vacuum distillation is a common chemical process in which quite a few accidents occnr due t o collapse of the glassware in which the experiment is performed. I n conducting experiments which demand vacuum, care should be taken to see that vacuum flasks of sufficient thickness are used. Flat-bottomed flasks should never be used and care should be taken t o avoid possible obstruction of the distillation condenser. I n collapse of glass flasks, glass is widely scattered and strong,goggles should be worn. Desiccators also frequently collapse under vacuum and should be guarded with wooden boxes with an outlet for the stopcock. I n operations requiring pulverizing, protection should be obtained in the form of an aspirator mask. Poisonous powders and chemicals, as potassium cyanides,
alkaloids, hypnotics, and unstable compounds, should be handled by the chemist and not by any assistants. By the use of the above precautions against fire, cuts, and poisons, the chemist can avoid most of the common accidents of the laboratory. In the case of experiments involving reactions in which the outcome is possibly dangerous, proper precautions should be taken. If the probable outcome is thought to be of a violent nature, i t is always a wise step to determine in a test-tube, with an infinitesimal amount, just how the reaction will proceed. If a tiny amount is first tried out, no dangerous results are obtained. If the first small amount causes no danger, a slightly larger amount can be used to see a t what point it becomes dangerous. 4 few trials of this kind are necessary to
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WHENSEVERING GLASSTUBING, IT IS ALWAYSBEST TO Pnomcr THE HANDSWITH A PIECEOR CLOTH
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determine the violence of any reaction and can be quickly performed. In other work of the chemist, there are always certain combinations of chemical and physical forces which are dangerous. Thus, the use of oxygen under high pressure, and heat through apparatus containing oil may result in v~olentexplosions. All laboratory pressure vessels, as autoclaves, should have safety valves or disks with the outlet pointed in such a direction that no accidents may befall. Common sense and chemical knowledge will enable the chemist to avoid many accidents which only he may foresee. In spite of all the countless possibilities of reactions of all kinds among the infinite forms of matter, the chemist can work in comparative safety if he will observe the dictates of common sense and apply his chemical knowledge to the problems of safety on hand.
