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Safety & Lab Tips
Everyday Lab Operations & Safety Tips
Lab operations involve a large assortment of operations. Many will seem strange and awkward at first, but weekly practice will soon make them familiar. That's the good news. The bad news, of course, is if you learn a procedure incorrectly (or incompletely) then repeated practice may build unsafe and dangerous habits.
The best way to correct a bad habit is to catch it before disaster strikes. Your instructors will be watching for bad lab habits and will talk to you about them as time permits. Unfortunately, it is simply not possible to watch any individual for more than a few minutes during a lab session. More help is needed and this is where you (and this appendix) come in. This appendix, and relevant sections of Padias (see especially p. 1-4 and p. 22-36), contain a number of tips for safe and efficient work. If you review this material from time to time, you will catch many of your own bad habits yourself and make your lab work safer and more successful.
Note: Students who routinely ignore instructions for safe lab work risk being dismissed from the lab.
Good manners make lab enjoyable and rewarding for everyone.
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Spills pose a danger to everyone in the lab (and especially to the custodians who clean the labs each evening). You must take responsibility for all of your spills. 'Responsibility' includes:
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The on-line Chemistry Safety Manual (section 3.3 - Dealing with Accidents) contains basic instructions for handling acid, base, and mercury spills. The Safety Manual (section 3.4 - Waste Disposal) and Padias p. 4 contain instructions for disposal of broken glass.
Organic compounds. Spilled organics present a special problem because these substances vary in volatility, odor, aqueous solubility, reactivity, flammability, and health impacts.
Solids can generally be swept up and discarded in the organic waste. (Traces of solid might be collected with a damp piece of paper and discarded, paper and all.)
Liquids are more challenging. If a small amount of a volatile liquid (say, a low boiling solvent) is spilled in the hood, no special action is necessary or possible; most of the liquid will evaporate before you can clean it up. Larger spills, and spills that occur outside a fume hood, should be treated with adsorbents (stored around the lab in "spill kits"). Consult the spill kit for instructions regarding how to apply the adsorbent to the spill, and how to clean up, label, and discard the used adsorbent.
Safe lab work requires attention to three potential ‘targets’: yourself, other people inside the lab, and the outside world. This page discusses each target and offers suggestions for performing specific lab operations more safely (see also Padias p. 1-3 for brief instructions).
Protecting the outside world. The most obvious step for protecting the outside world is to dispose of all materials properly (see Disposal). Another, less obvious step is avoid lab operations that pollute the environment.
Unfortunately, a total ban on lab pollution is hard to achieve. Volatile solvents, even when used in fume hoods, pollute the atmosphere. Compounds that go down the sink ultimately pollute streams and soil.
A perfectly non-polluting experiment may be impossible, but this does not make us less responsible for the outcome. If we cannot eliminate unsafe chemical emissions from the Chem 201/202 lab, we should at least try to minimize them. This principle has guided the selection and design of our experiments, but more needs to be done. You must also play your part and make sure that all chemicals within your control are disposed of properly.
Protecting yourself and other people inside the lab. There are three things you can do to keep yourself and others safe while working in the lab:
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'Avoid dangerous operations' is an extremely important principle, but how does it work? How do beginners, in particular, recognize a dangerous operation? The following list provides safety tips organized by the type of operation.
Measuring compounds
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Transferring compounds
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Heating compounds
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Applying a vacuum
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Water hoses
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Glassware
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Every experiment in your notebook is supposed to contain hazard information and handling instructions for the compounds that you will be working with. The question that vexes a beginner is how much hazard information, and which handling instructions, really need to be listed. Do we really need to write down:
Water - hazardous, do not inhale
One way to approach this problem is to recognize that there is a spectrum of lab hazards. Some are routine. Others are extreme. The routine hazards usually don't require special mention in your notebook, but the extreme hazards always do.
A routine hazard is one that is widely recognized. You don't have to tell a fireman that wood burns, but you might want to tell him that the bottle of liquid in the fume hood does. A routine hazard is also any hazard that is adequately managed by following the basic rules of our lab: wear goggles and perform all experiments in the fume hood. More on this idea later.
An extreme hazard is any hazard that might not be widely recognized, e.g., the flammable liquid in the bottle, the toxic gas in the gas cylinder, the metal that explodes on contact with water. It is also any and every type of hazard that demands more attention than "wear goggles, do all experiments in the fume hood." If our routine practices will not keep you safe, then you should list the hazard in your notebook and list appropriate handling/disposal instructions as well.
Let's make these distinctions between routine and extreme hazards a little more explicit by considering three particular types of chemical exposure: eye contact, inhalation, and skin contact.
An example of a routine eye contact hazard is a compound that accidentally gets squirted into your eye. Eye contact with foreign substances is always very bad. This explains our basic rule: wear safety goggles at all times. However, because eye contact is a routine and universal hazard, you do not need to list "eye contact hazard" next to every compound in your notebook.
On the other hand, there are exceptions that must be considered. A compound that is especially reactive towards eye tissue should be regarded as an extreme hazard and should be listed as such in your notebook. All compounds that are labeled as lachrymators belong in this category. Lachrymators irritate eye tissue to an extreme degree and mere vapors of a lachrymator can initiate eye irritation and damage. Notice that goggles, our routine method for preventing eye contact with foreign substances, do not control vapors well. The inadequacy of goggles in dealing with lachrymators is a perfect indication that lachrymators need to be listed as extreme hazards in your lab notebook.
Similar thoughts apply to inhalation hazards. Our routine assumption is that breathing large amounts of any organic vapor is bad for you. To provent this, we have you perform all experiments in a fume hood.
Does this mean you can skip listing "inhalation hazards" in your notebook? Not necessarily. Notice that "perform all experiments in a fume hood" does not eliminate the possibility of taking a compound outside the hood to weigh it, dispose of it, or store it. A compound that produces toxic (or odorous or explosive) vapors should never be taken outside the fume hood. Moreover, every person who enters the lab ought to be informed that you are working with a compound that produces dangerous vapors. These kinds of compounds are not adequately managed by our basic lab rule, so they should be regarded as extreme hazards and appropriate hazard information and handling instructions (which may include special procedures for measurement, storage, and disposal of the compound) must be entered in your lab notebook.
Skin exposure poses a different kind of problem. First, skin may tolerate more chemical exposure than eyes and lungs. This explains why we don't have a basic rule regarding gloves. By now you should realize what this means. If the routine procedure (no gloves) is inadequate for a given compound then the compound should be treated as an extreme hazard. It is your responsibility to decide when gloves are appropriate. You should make a special effort to identify corrosive and/or strongly reactive reagents (like aqueous base), or strongly penetrating agents (like DMSO), or potential allergens, that might present significant skin hazards and list this information along with suitable handling instructions in your notebook.
This discussion hardly exhausts the list of possible lab hazards. Here are some others that should be listed in your notebook: 1) extremely hot or cold objects (contact with these can damage your skin; hot objects can also initiate a chemical reaction, fire, etc.); 2) any procedure or compound that can react vigorously or explosively with other substances; 3) flammable compounds; 4) water-sensitive substances (compounds that react quickly and exothermically with water); 5) any procedure that yields a gaseous product (gas confinement builds pressure inside an apparatus and runs the risk of explosion; also, some gases, like hydrogen, may be chemically reactive).
