m f e t y in the chemkd laboratory
edited by MALCOLM M. RENFREW University of idaho MOSCOW, ldaho 83843
An Undergraduate Chemical Laboratory Safety Course L. Jewel Nicholls University of
Illinois at Chicago Circle, Box 4348 Chicago, IL 60880
In all college laboratory courses, students are introduced to safety principles as soon as they are assigned laboratory work involving chemicals. This continues throughout their lives as they work in laboratories and plants. At some point each person becomes responsible for his own laboratory safety and that of others. This means that he must be able to make judgments based on sound principles or on research into specific hazards. He must be sure enough of himself that he can advise others with confidence and authority. Safety topics which are useful to an undergraduate student are similar to those presented to industrial groups for plant
safety. However, the types of assignments and class exoeriences which will helo the student to apply chemical safety prinripl~s ro his rhenkal laboratory operations are of a deeper nature and involve more uf a problem-solving approach. How does one get such a course to fit in with a chemistry curriculum? Since the scope of such a course is based upon chemical skills at the eolleee level material mav be l resented a hivh helps students to understand safety at a mow qumlitativeand theoretical level by applicatiun of principles of equilibrium, kinetics, free energy of concentration, and gas laws to real situations. The safety course offering at UICC is Chemistry 283, a two-quarter-hour course which meets two hours a week usually in a classroom, but occasionally in a laboratory. The offering is an alternative to the required literature course for the BA degree. It is an elective for Bachelor of Science candidates and students in other fields, such as biology and engineering. The prerequisite is organic chemistrv. Students who have taken the lab safety cuurse are mainlv those interested in industrial ehrmistry. However, students interested in teaching or graduate srh~mlhave also taken it. I feel it will be useful to adopt the texts: "Prudent Practices for Handling Hazardous Chemicals in theLahoratorvn . (.1.).. Volume 3 of "Safety in the Chemical Laboratory," edited by N. V. Steere (2),and Volume 4 of "Safety in the Chemical Lahoratory," edited hy M. M. Renfrew (3). "Prudent Practices ."was published by the National Research Council with input from prominent scientists as an alternate approach to OSHA regulations, since conditions in research and teaching laboratories differ from those in industrial settings because of the different scope, untested chemicals, level of competence, and short exposures involved. Volumes 3 and 4 of "Safety in the Chemical Laboratory" have in-depth articles on many of the topics which lend themselves to good problem-solving exercises with which chemists has the must deal. "Prudent Practices advantage uf good organrratam, reasonahle p r m , guod hbl~ogmphy,and recent publrcation. I have been using as a text Volumes 1,2,3 edited by N. V. Steere: "Safety in the Chemical Laboratory" (2). A course outline using this as text was published by Lowry (4). This has a few drawbacks hut has been the ~~
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best choice up to this time. It is not organized as a single text, and the articles range in depth and applicability. It has the advantage of in-depth coverage of relevant topics prepared by experts in that field. A combination of "Prudent Practices ." and Volumes 3 and 4 of Safety in the Chemical Laboratory give the organization plus the depth required for such a course. Neither has problem sets or sets of questions useful for class assignments. Another hook which may he used as a text is a paperback by Green and Turk (5) containing basic material which may be supplemented as I have indicated in Tables 1,2,and 3. The text by Meyer ( 6 )is useful for classes
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(Continued on page A3021
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L. Jewel
Nlchoiis received her BS hom Monmouth College and her PhD from the University of iilinois at Chicago. She is presently the Coordinator of the Undergraduate LabaatwieJandS t m m a t the University of iilinois at Chicago Circle where she developed the course she describes in this .oaoer . under the ausoices of an NSF grant rler researcn interests lie in me t eid ol onorganic chemistty particularly the rtereochemisq of metal mpierer emmining chirai donor atoms, as well as in thedeveiopment of materials for safety eoumes and safe laboratory experiments.
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Volume 59
Malcolm M. Renfrew draws on varied industrial and academic experiences in his approach to good safety practices. After graduatestudy at the University of Mime wta, he was a supervisor of research and development with DuPont and General Mills: then an administrator and teacher at the University of idaho, his Alma Mater. He is active in the American Chemical Society. including service with the Commitlee on Safety and the new division of Chemical Health and Safety. He now is professor emeritus of chemisby and is patent director of his University's ldaho Research Faundation. Inc.
Number 10
October 1982
A301
Table 1.
Topics and Assignments for a Laboratory Safety Course Lecture Hours
To~ic w i t h less background in chemistry-fire fighters, for example. It explains emergencies in terms o f basic physical properties. T h i s book has t h e advantage t h a t it has problem sets a t the end o f each chapter. A t e x t b y Fuscaldoet al., (7) could be used in a courseat the college level where the emphasis i s o n biohazards. In addition to this content it bas excellent sections o n radiation hazards and behavioral factors in laboratory safety for personnel which are n o t covered as well, if a t all, in other texts. Ihave worked u .o a svllabus based uoon ' P r u d m r P r o r t w s . . ." 1 1 , and the t h i n l and fourth w l ~ m r of i "Safrt) in the Chemical LR~UTAI~W)." (2. 3,. T h e number uf Ircturpa for each topic, pages assigned, and related class or assigned activities are found in Table
.
Pages Prud. Pract. f 11
W i n s t o n C. Nottingham Universihl of the District of Columbia Washington. D.C. 20008 W h e n using do-it-yourself (D-I-Y)
or "homemade" electronic laboratory equipment it is sometimes possible to experience a severe electrical shock. An installed fuse serves as a safety device t o protect the equipment; however, it usually does n o t respond r a p i d l y enough t o ensure personal safety. T h e Ground F a u l t Interrupter I G F I ) i s desiened t o react almost instantlv t o a ~, e k u n d fault or short and will ~ ~ t ~ r r the u p fluw t o f current hefur? a lethal s h ~ c koccurs. E l w t r i v i t y follows the p a t h o f least resistance. I f a ground f a u l t occurs, some o f the n e u t r a l current w i l l flow in the grounding p a t h (grounding conductor oi person's body). Therefore, less current w i l l flow in the neutral wire t h a n *illflow o n the "hot" wire. I f the difference i s 5 f 1 mA, the GFI w i l l trip in a few milliseconds. Here, the GFI's function serves t o stop the current flow before one receives ~ e r s o n a l injury. GFI's are available in several different types, i.e., circuit breakers, replacement receptacles, and portable plug-ins. The cast will vary, starting a t about $30. T h e m i n i m a l cost associated w i t h t h e replacement receptacle type GFI makes it a bargain for the increase in safety. A l l G F I devices come w i t h clear and complete wiring instructions and a test procedure. ~
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EDITOR'S NOTE:
Campus safety officers may take a d i m view o f doit-yourself electronics and also m a y have established procedures o n the use of ground fault interrupters.
A302
Journal o f Chemical Education
Pages Renfrew (3). VoI. 4
Introduction Toxicology Personnel Protection Corrosive Chemical Hazards Flammable Hazards Explosive Hazards Storage and Disposal Pressure Systems Equipment and Radiation Ventilation and Monitoring Philosophy of I ah Safehr
Table 2.
Safety: A Protective Device for D-l-Y Electrical Workers
Pages Steere (21 Vol. 3
Problem Sets
A. TOXICOLOGY PROBLEMS Answer the following questions as completely as possible showing calculations where required: 1. Consider methacryiic acid f w which emies may be found in many toxicolagy references(see reading lisB. a1 What IS the east Concentratton *hch may cause a dean in humans? bl It Inere were no aata from stmes on h.mans. what mognl you say aboffl me tox c effecl on humans? From animal data? C) What are the toxic effects on (a) short exposure? (b) long exposure? d) What precautions must one take if one is to work with methacrylicacid? e) Using any source of data, cite the toxicity of methacrylamide as it compares with mathacrylie acid. Think of a reason why this may be true based on logic from Carter and Fernando (6). 2. The TLV for chloroform is 50 ppm (240 mg/M3)at 25" a) Translate this to vapor pressure in mm Hg. b) This is a ceiling value. Haw is the TWA related to the TLV? 3. The TWA for orthotoluene is 5 ppm (USOSair).if the usual concentration of orthotoluene is 1 ppm. except for a 30-minute period when the level is 150 ppm, is the TWA exceeded? Show calculations. 4. Disc~ssthree wavs in which toxic substances interfere with metabolism. 5 A combmat on of mcrel wbonyl and dnoorane leakw ntothe a r n a aoorstw Mon torlng4evces showed tnat the concernrat on of mcrel caroony *as 0 0007 ppm an0 lnal of 0 borane 0 05 at 25' Ass~methe effect is add w e an0 calcu ate rhether tne thresnod irmot value was exceeaeo 1-V values are part of the assigned reading. 6. What is a teratogen? Are teratogenic effects limited solely to exposures in women? 7. HOWare mutagenic effects different from those of teratogens? Compare both to embryofetatoxins. 6. If the LOSOfor hexanoic acid is 2050 mg/kg for a rat, what approximate dose far a 160-pound man mioht have a similar effect? a) What assumptions must be made in the extrapolation of toxicihl data from rat to man? b) What precautions, if any, must be taken when working with hexanoie acid? 9. What accidental means of injection of toxic agents is most likely to be the case in a typical research or teaching lab? 0
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B. STORAGE PROBLEMS 1. If YOU were to a m g e a storage area for a kilogram w m e of each of me classes of materials listed below, indicate the kind of storage you would choose, and what kinds of materials must be ananged away from &em Ifalphabetical listings an shelves is impwtant, how many of these separate listings will be most advantageous so that dangerously incompatible substances will not be in contact with each Other. Other choices of storage facilities may be refrigerator, solvent cabinet, or exterior Separate Storage building. Inorganic oxidizing acids, fiammable solvents, solid hydrocarbons, cyanides and sulfides, explosive salts, pyrophoric substances, pemxides, inorganic concenfrared acids, inorganic concentratedbases, liquid aliphatic bromides. and organic smines. 2. FM each of the classes of chemicals in the problem above. list two examples. 3. The TLV for rrpentane is 1000 ppm. At what temperature will the vapor over liquid pentane equal this value when in equilibrium? spentane vdmm) Tl°C) 181 0 760 36 Hint: either use the Clausius-Clapeyran equation or a plot of log p vs TIT, yielding a Jtraighl line. Why? Heat of vaporization of sheptane is +6500 cal/mal.
Table 2.
Contlnued
4. Combustible limitsfor rrpentaneare horn 1.4to7.4%volume inair. If 100 ml of liquid pemane were to evaporate in a closed cabinet having dimensions 1 X 1.5 X 0.5 M, would this be a combustible mixture? 5. What orooerties of safew cans make them desirable for disoensers of flammable liauids? 6 - SI propenes of retr geratorr which arc necessary to a to* storage of flammable W a r . 7. What are two propen esat llammaoie oqulos wnlch make Inemmoredangerous man sol dmateroals which are easily burned? 8. Explain the difference between unstable and reactive compounds. What kind of special storage problems do these compounds pose? 9. Describe differences in the closed cup and open cup test In procedures, results, and applications. 10. HOW might flash point data be misleading when working with solvents in the presence of liquid oxygen? 11. What is the auto-ignition temperature in terms of laboratory systems and precautions? ~
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C. ENERGY PROBLEMS Work out these problems using the data below: 1. For a mixture of ethene. CpH4,and oxygen (not air): a) Write a complete, balanced equation far stoichiametric combustion. b) Compute the enthalpy change of this reaction at 298.15 K. (Assume product water is in the gasems statel. C) Compne tne ad~aoatlc flametemperatre of lhis reanion. One memad s lo Lse me Compute ' to so ve me c ~ coequal on involved rhen all three terms are program ' S P E A ~ ( E A ~ Y(la used. 2. Assume the composition of dry air to be 78 mole % nitrogen. 21 mole % oxygen, and 1 male % aro(m: -.
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a) Write a camp ete. oalanceo equal on for stofcnomeldc combust.on of ethene n dry aa. b) Compute h e enthalpy cnange of lhls reaction at 298 15 1( IAssbme product water lo in the gas state). C) Compute the adiabatic flame temperature of this reaction. d) Compare the adiabatic flame temperature of this reaction in pure oxygen to that in air. i) Why is there a difference? ii) Discuss the above difference in terms of kinetics, ventilation, special precautions, etc. 3. For the dewmposition of 2,4-dinitrophenol.C.H4N$Jqs, and nitromethane. CHsNOs, in the absence of air: a) Write a complete, balanced equation for stoichiometric decomposition for each substance. Use rules in the article by Stull in Renfrew. Voi. 4, (3Lp. 1. b) Compute the enthalpy change of each reaction at 298.15 K. (Assume product water is in the gaseous state) C ) Compare AHof decomposition per gram of each of the two compounds. ESSENTIAL DATA A. Specific Heat Equation: Cp (calldeg-mol)= a bT+ c T 2
+
AH= X p A T 8.
cability of toxicity and epidemiology data. In addition, calculations involving exposures to several related chemicals and the relationship of vapor pressure, TWA, and TLV help stndents to learn to applv the values in tables, Problems involving storage practices include calculations of the relationshios between v d p v p w w m and temperature and expo. surr l ~ m m flammal,le limit*, and storage uf clases of chemical materds. I'ruhlrm i n volving chemical storage help students to think in terms of chemical reactivity in considering storage arrangements. The problem set on energetic chemical systems includes calculations of adiabatic flame temperatures of combustion, decomposition energies, and comparisons of energetics of unstable compounds. Actual laboratory experiences may be fit into a course of this limited scope with beneficial results. Combination of a brief lecture with such experiences as use of goggles, eye washes.. fire blankets. fire extinrmishers. and hrrathlng masks; handing of gas cylinders; ancl (,ther suscrptihle comtestInd p,,,,nds for prrorLdes; tPitinE of tumr htx,ds: and use of available testing apparatus such as explosimeters, ~~i~~~counters, or mercury
Enthai~vof Formation. callmol(298.15K)
Ethene (g) Water (g) Carbon dioxide (g) Carbon monoxide (g) Nitromethane (I) 2.4dinitraphenol(s)
+12.496 -57.798 -94.052 -26.416 -21,280 -51.500
C. Specific Heat Equation Constants Specific Heat Equation Constants Substance
a
Water (9) Carbon dioxide (g) Nitrogen (g) Araon la)
7.17 10.55 8.66 4.969
Examples of problems are listed in Table
2. Problem sets are useful for reinforcement of concepts developed in class discussions. Many texts give general information and do not go into problem-solving and calculations which may help students to understand
b
There arr man" \,ideotaprs,slide set$, and film., - ~ ~ ~courip, .rhpse are ~ ~ visualize situations or demonstrate techniques for using apparatus. Some, for example "Mercury Hazards9'and "ABCD's of Fire Extinguishers," follow a script to tell a message and were photographed by a staff photoeraoher. Other UICC slide sets are collecti& bf slides of accidents, situations in labs, illustrations from books, and other private sources, many of which may not be duplicated, others are combinations f, many types such as graphs, diagrams, illustrations from texts, clinical cases, and excerpts from accident reports. A list of audiovisuals which I found useful can be found in Table 3. In-deoth articles on various ohases of ~
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on current accidents and explasions, laws and regulations, and techniques. Additional readina may he assigned in some areas. For exa&ple, a reference on toxicity of chemicals used in academic laboratories hv Carter and Fernando (8)is an as-
Enthalpiss of Formation for Selected Compounds Compound
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concepts. Toxicology problems involve use of safety literature t o find toxicity data for a chemical or class of chemicals and are designed t o familiarize students with standard safety references and to help students make extrapolations and judge validity and appliVolume 59
which everyone should have is in compact form in the ACS booklet: "Safety in the Academic Chemistrv Laboratories" (9). An excellent referen& book is Bretheriek's "Handbook of Reactive Chemical Hazards" (10) which should he in all libraries. An assignment, "Preparation for a Hazardous Chemical Experiment," is a culmination of most of the topics in the course. Questions in the final examination are based on reading rather than numerical calculations and are similar t o those used by Lowrey ( 4 ) , but oart of it is avisual oerusal of set-uos of hazardous situations in the laboratory or slides of real situations which should be reeognized. For example, a set-up for adistillation with obvious hazards such as outdated ether, paper litter, poorly fitting heating mantle, frayed wires, cracked flask, or poorly
(Continued on page A3041 Number 10
October 1982
A303
Table 3.
Videotapes, Films, and Slide Sets
Topic
Length
TYP
Ignorance Isn't Bliss Toxicology Laboratory Hazards and Safety Procedures First Aid for Chemical Exposure t o the Eyes ABCD'S of Fire Extinguishers The Double Edged Sword Fume H w d s Compressed Gas Cylinders Mercury Hazards Our Hidden Natural Resources
I 0 min 15 mi" 59 mi"
V
UICC (12,
S
V
UICC' Geological Survey (13)b
15 min
S
Encon Mfg. Corp. ( 1 4 )
10 mi"
S
20 min 10 mi" 10 min 10 min 20 min 45 m i n
V V
UICC ( 1 2 , NIH ( 1 5 ) UlCC ( 12, UICC ( 12,
Flammable Storase Hazards
Source
V
UlCC ( 12, EPA (16)
S F S
UICCd
~hese slides are ol local interest a may not be repmduced. Similar slider m y be obtained w made by anyone to fit with a lecture by copying graphs, textbook illuslrations, or by contact with Dcal =few officiais for pictures of local a*
dens. b T h are ~ several ~ short seauencer which are verv useful: Fume Hwds. 7.5 min: Eve Wsrh Stationa. 2.25 mi": nergency Shower, 2 min; ~ c i Spill d Remactmenf, 4.5 min: and solvent ~ires.6.25 min. copies of this tape may be mined by sendiqa 60min. 3lCin. blankvideoL%pecassette w h yourrequest to PhoeDe L Ham U S . Geolqical Swey. 0. Box 25046. MS917. Denver FederaiCenter, Denver. CO 80225.
:cured water hoses may he viewed by the udents with a request that they note as #anyhazards as they observe. This work is supported by a National cience Foundation LOCI grant. I wish to lank the NSF as well as memhen of the hicago industrial community including the hicago Area Technical Council. iterature Cited I) National Research Council, "Prudent Practices for HandlingHazardousChemicals in the Laboratory: NationalAcademy Press, Washington, DC., 1981. 2) Steere. N. V. (Edilar),"Safely in t h e Chemical Laboratory: Journal of Chemical Education. Fdston, PA 1834Z.Vols. 1. 2,and3,1967. 1970. 1914. 1) Renfrew. M. M., (Editor), "Safety i n t h e Chemical Lshoratory." Journal of Chemical Eduration, Eeuton, PA 18042. Vol.4, 1981. 1) Lawry, G. G., J. Chom Educ., 55. A235 A263 (1978). i) Green, Michael E., and Turk, Amm, "Safety i n Working with ChemicaLs: MeuniUanPublishingCo., Inc.. New Yurk. 1978. i) Meyer. Eugene, "Chemistry of Hazardous Mstorials." Prentice Hall, Inc.,Englewwd Cliffa, NJ, I977.
NIOSH/OSHA HAZARD GUIDES Information about the health effects of specific chemical substances can he found in the new "NIOSHI OSHA Guidelines for Chemical Hazards." The Guidelines are intended togive people in occupational health programs summary information including technical data on exposure limits, routes and symptoms of exposure, effects of overexposure, medical sur-
A304
Journal of Chemical Education
(7) Fu8caldo.Anthony A,. Erlieh, Barry J., and Hindmen. Barbara. "Laboratory Safety-Theory and Practice: Academic PIPS. New York, 1980. (81 Carter, D. E., and F e r n a n d ~ , Q . , ~ ~ C h e m i c a l T ~ x i i I ~ . Part I. Organic Compounds: J. CHEM. EDUC. 56. 284 (1979): and "Chemical T o x M w . Pan 11. Metal Toxieity"J. CHEM. EDUC.Y.490(19791. (9) "Safety in the Academic Chemistry Laboratory", 3rd Ed.,American Chemical Society. Washington. DC 20036, 1979. (10) Bretheriek, L. (Editor). "Handbwk of Reactive Chemical Haxards: 3rd Ed., Butterworth's, Londnn~Boston.1981. (11) "NIOSHIOSHA Guidelines for Chemical Hauvd."(3 Vol. 1981). Singlo mpiesarefreefrom NIOSH,Publicationa Dissemination, 4676 Columbia Parhay. Cincinnati. OH 45226 Plesseendm aself-addressed mailing label. (12) Uniueniqv of Illinois a t Chicago. Chemistry Department, 1980. (13) US Geological Survey, US Depart of the interior, Denver, CO 25046 (1979). See Note Zon Table 3. (14) The Encon Mfg. Corp.. Houston. TX. (15) Bureau uf Radiological Health, NIH, Rockdle, MD 20&52. (161 Film Comm. 108 W. G r a d Chicago. IL 60610. dis-
.
Irih,,tnr .... . .-.
(17) Cohen,S. andPietar,S., Speakeasy ComputingCorp. Chicago ll9'79).
veillance, monitoring, toxicology, chemical identification and respiratory and personal protection equipment. Chemists and teachers of chemistry should have easy access to these guidelines. The three-part work covers the 320 hazardous chemicals regulated by the Occupational Safety and Health Administration. Single copies are free from NIOSH. Publications Dissemii n , 4 6 . l i Parkway, Citainnati. Ohiu 45?26. Plrxvr mcloae a self-addre-sed mailing latwl.
