How Safe is the Air We Breathe in Our Laboratories?
There is a growing attention to the hazards involved in chemical education and employment, as evidenced by features on safety in the chemical laboratory, in this and other journals. Although such articles are in many respects most laudable, one can sometimes detect a fervor which is less than discerning in its assessment of what are significant and what are trivial hazards. If emphasis on the latter is not avoided, the "unconverted" in safety matters may well react in an uncooperative and obstructive manner. Naturally, in safety matters, there will be a tension between institutional responsibilities and needs and individual responsibilities and needs. Some research workers may, indeed, feel that safety rules in their institution may largely be a tiresome smokescreen of petty individual responsihilities and restrictions, which camouflage an institutional desire to avoid the expenditure of money on the creation of safe working conditions. Clearly, the responsibility in this area is dual, hut I do wish to draw attention to a very widespread situation in which institutional responsibilities to employees and students are often discharged quite inadequately. I refer to the responsihility of maintaining clean, pollution-free air in the working areas in teaching and research lahoratories. My lack of reference to the situation in the factories and plants of chemical industry, is not because I helieve the situation there to be exemplary, but because I believe that the problems of that area are rather different and would be best dealt with by a person more closely connected to that scene. Unfortunately, the average school and university chemistry laboratory, derives its basic arrangements for the dispersal of noxious gases and fumes from the days when chemistry was ingloriously referred t o as "Stinks"and the smell of H2S and the effluvium of boiling mineral acids were the signposts to the chemistry lab. The present day lahoratory has to contend with a much broader range of volatile hazards. Organic solvents, volatile organometallic and metal-organic compounds, pesticide derivatives, carcinogens, teratogens, heavy metal vapors, nerve gases, and novel synthetic compounds of unknown toxicity, are now the random constituents of the fumes from many university and industrial research laboratories. T o a lesser extent, this can also be the situation in teaching laboratories. The fume cupboard of the research laboratory differs from the devices for fumedispersal in industry, insofar as the former is the recipient of a much more sporadic influx of diverse material, whereas in the case of industry, a much narrower definition of pollutants is usually possible a t a given location. While the effluent from research and teaching laboratories may not contribute appreciably to a city's overall pollution problems, there are some potentially very serious local implications. The problem which I particularly want to draw attention to, is that of fume dispersal from the exits of fume cupboards and associated ventilation systems. Fume cupboard design is itself very important and many readers will have experienced totally ineffective systems a t some time during their professional lives. Although fume cupboard design is slowly improving under the influence of a more informed approach to aerodynamic principles and practicalities, the problem of dispersal of the effluent fumes is still deplorably ignored. It often seems as if institutions feel that they have met their obligations when noxious fumes are expelled on to the roof or are blown hopefully out a vent in some window.
The consequences of such naivete are readily manifest. Most chemists are aware that in certain wind directions and velocities, the air in various parts of their host institutions becomes contaminated with fume cupboard effluent. Downdrafts of air carry fumes expelled a t roof level down the face of buildings, fume extraction systems draw this air into the building, service ducts assist recirculation, and the net result is a com~lexsvstem of fume recvcline . with disauietine implicatiois. ~ e ; ycommonly, little attention is baid to the problem until some volatile substance with an obnoxious smell is introduced into the system. The automatic reaction to this affront is usually one in which the offending group is asked to desist from releasing smelly compounds into the fume dispersal system. The cynical message which is picked up from this quite inadequate response, is that toxic volatile species are O.K., but strongly smelling gases are not! The smell is only a symptom of an inidequate fume dispersal system. The real danger arises from the recycling of fumes, and the smell should he recognized as an occasional and unreliable reminder of the existence of a potentially dangerous situation. It is conceded that institutions vary greatly in the adequacy of fume disposal and in the stresses which they put on the fume dis~ersalarraneements. On the extreme edee of incredibility iie those lat;;,ratories whose de*iyner, ;surely not chemists!) haw placed air intakes for lalx~rntories,ot'fices, or lecture theaters new to fume cupboard exits. Also of concern are recirculating air conditioning systems which in the interests of economical operatirm me designed to recycle laboratory air with only minimal injection oiiresh air. Next in line ior censure are those occasional chemistry departments which solve the vexed prohlem or waste solvent disposal by theirresponsihle method of evnpnrating the noxious material via fume hoods possessinfi inadequate dispersal chnracteristics. How far do existingfume dispersal systems fall below recognized standards? Following the work of Hawkios and Nonhebel? Turner. in his Workbook of Atmosnheric Dispersion ~ s t i m a t e s prescribes j the use of smokestacks 2.5 times the height of a building in order to satisfactorily disperse fumes. In this context, it needs to be remembered that the users of neighboring houses and buildings also have a vested (and probably legally definable) interest in this issue. If taller buildings surround the laboratorv - buildine.-. then more stringent standards need to apply. How many chemistry laboratories meet the above specifications? The list would probably he very short. What medical consequences may the average student or laboratory employee expect? The answer is unclear as the hazards are difficult to quantify. Unless air analyses are carried out for the multiplicity of more or less volatile and variable contents of fume hood exhausts, it is quite difficult toeven hazard an apriori assessment. There are, however, some warning signals. The tragic death by smallpox of Janet Parker3 who had been employed in the Anatomy Department a t Birmingham University and the tragic suicide3by the Head of the nearby smallpox lahoratorv carrv a sienificant messaee for chemists. even though the accident, k that case, wasmicrobiologicalin nature. Two points from the report of the investigating com~~
~
.~
'Hawkins. J. E.. and Nonhebel. G.. J.Inst. Fuel. 28.530 11955).
Volume 56, Number 10, October 1979 / 667
mittee are particularly ~ e l e v a n tFirstly, .~ the virus was evidently transmitted from the smallpox laboratory to the victim's working area on another floor, via a flow of air through a service duct. Secondly, thevictim was engaged in work which had no connection with the toxic hazard. The implications of the above tragedy in buildings housing chemistry laboratories are obvious. Because the effects of some chemical toxins are chronic rather than acute, a false sense of security unfortunately seems to prevail. One hopes that tragedies such as the above are not the necessary pre-
668 1 Journal of Chemical Education
requisites for a more responsible institutional approach to the maintenance of clean air in the workplace of the chemist. The author takes full responsibility for the sentiments expressed in this article, hut would like to express his thanks to Dr. F. C. R. Cattell for a number of helpful discussions on the environmental aspects of the problem. Terry I. Quickenden Department of Physical and Inorganic Chemistry University of Western Australia Nedlands, W.A., Australia 6009
