Chemical Safety Questions
From ESF FAQ Wiki
What does UVM recommend as a guide to safety in laboratories?
Prudent Practices in the Laboratory by the National Research Council at http://www.nap.edu/openbook/0309052297/html is used to guide chemical safety practices at UVM. Paper versions are available in the UVM libraries and on loan from the Environmental Safety Facility.
Information about the safe laboratory use of specific chemicals can be found in the Laboratory Chemical Safety Summaries at the Howard Hughes Medical Institute site http://www.hhmi.org/about/labsafe/lcss.html
What are the most serious chemical storage problems found in UVM laboratories?
The most common, potentially dangerous mistakes are
- storing organic acids with oxidizing acids (such as glacial acetic acid with nitric or perchloric acid),
- storing flammables in household appliances,
- storing chemicals in the fume hood,
- storing hazardous liquids or oxidizers with no secondary storage container, and
- leaving chemical containers unlabeled.
If you're not clear on the meaning of any of these terms, review the Chemical Safety in the Laboratory online course available at http://esf.uvm.edu/courses or contact us at mailto:esf@uvm.edu.
What is the problem with storing ethanol in a refrigerator?
Because flammable solvents have very low flashpoints and flammable limits (lowest vapor concentration that can be ignited with a spark), a normal refrigerator does not provide safe storage for them. Ordinary refrigerators commonly have many sources of ignition (e.g., thermostat, interior light, light switch on the door, defrost heater, defrost control switch, the compressor unit, and the fan). The ignition sources have ignited trapped vapors from poorly sealed or broken containers and caused harmful lab explosions.
What kinds of containers can I use for chemical secondary containment?
It is important that the integrity of the secondary containment container is not compromised by the chemicals that are stored in them and that the containment volume will capture all of the liquids if the primary containers break. For most chemicals high density polyethylene (HDPE) or polypropylene (PP) plastic work well, are inexpensive, and relatively unbreakable.
It is also acceptable to use a glass or (compatible) plastic beaker for a single (or a few small) container to maximize use of storage space. A cafeteria tray or similar item is not acceptable both because of the unknown nature of the material used in the tray and the low sides and thus containment volume.
Ultimately, your choice depends on the chemicals you are storing. For example, hydrofluoric acid should be stored in a plastic bottle with plastic secondary containment, not in glass, because hydrofluoric acid impairs the integrity of glass.
Can I use a mercury thermometer in my laboratory?
Mercury is an neurotoxin and environmental contaminant. Mercury release is a particular problem from broken laboratory equipment that contains mercury. Complete clean-up of mercury presents serious hazards and can be expensive to clean-up. For this reason, UVM's goal is to minimize the amount of mercury used in its laboratoriess. Environmental Safety's (ES) Mercury Thermometer Swap Program was developed to encourage laboratories to, at no charge, exchange mercury thermometers for non-mercury replacements.
If it is necessary to have an extremely accurate thermometer, it is acceptable to use a mercury thermometer. First, consider using an electronic device to measure temperature. If a mercury thermometer is necessary, please buy one that is coated with teflon or plastic so that the mercury will be contained in case of breakage.
Many times, new equipment (such as water baths and ovens) comes with a mercury thermometer at no extra charge. If the degree of accuracy does not require a mercury thermometer, please replace it a with a non-mercury alternative provided by the ES Mercury Thermometer Swap Program. This will help to avoid expensive clean up should the thermometer break in the machine. It is not uncommon for mercury contamination from broken thermometers to require disposal of an entire piece of laboratory equipment. When new equipment arrives in your laboratory, check for and promptly exchange mercury thermometers.
If you have mercury thermometers that you would like to exchange at no cost to you, contact us at mailto:esf@uvm.edu
Can I use peroxide test strips to keep peroxide forming chemicals beyond the manufacturer’s expiration date?
A variety of laboratory chemicals can form explosive peroxides crystals upon exposure to air, light, or through age. Obviously, these chemicals must be handled with extreme care and managed carefully to avoid this hazard. Examples of such chemicals are listed at http://safety.scs.uiuc.edu/work3.htm
Peroxide test strips are commercially available to test for the presence of peroxides. However, UVM policy is that laboratories must adhere to the original manufacturer’s expiration date and dispose of the chemical through the Environmental Safety hazardous waste disposal system no later than this date. While it is unlikely that these materials are safe one day and dramatically unsafe the next, to maintain a predictable and consistent margin of safety, we recommend you manage your inventory and plan your purchases of these materials according to the manufacturer's recommendations.
How much material in a fume hood is too much?
You should keep the absolute minimum of material necessary to conduct your procedure in your fume hood. This will ensure that your fume hood can effectively capture and exhaust chemical fumes generated in the fume hood. While your hood may pass certification, this does not assure that it's protecting you from chemical fumes adequately because the hood's function can be disrupted by the way it is used. For additional information, see the UVM Chemical Fume Hood Hanbook. For training, attend ESF's Advanced Training course.
The bottom line: Do not use a fume hood for chemical storage and remove excess equipment while it is being used.
Can I designate a part of the laboratory for food consumption?
No food or drink can be stored or consumed anywhere in a laboratory that hazardous chemicals or infectious agents are present. We also recommend against marking off a portion of the laboratory as a clean area; the clean area should be separated from the chemical use space by walls and closed doors.
Do I have to label all containers of chemicals, even the ones with which I am currently working?
Yes. Labels are critical for the safety of both people working in the laboratories and also for people who maintain or have to respond to emergencies in the laboratory. Since these events are unpredictable, labels should be on chemical containers at all times.
There may be ways to make the labeling of chemicals and mixtures easier. For example, if it is something you use repeatedly, have completed labels on hand to attach and remove from containers as needed. The orange labels supplied by Environmental Safety have semi-sticky glue that makes them removable and reusable for such purposes.
Do I have to label the contents of stills and other complicated glassware and equipment?
Yes, every container of a liquid, solid, or gas in the laboratory must be labeled completely with the full name of chemical, hazards and date. This is for the benefit of people who are working around you and people who may have to respond to an emergency in the laboratory. In some cases, signs identifying the chemicals and associated hazards may work best.
Is there any time a chemical container need not be dated?
Yes, there is one exception to this rule. If you have a container for ‘daily use’ which is filled in the morning and empty by the end of the work day then simply write ‘daily use’ rather than changing the date every day.
Do I have to use the ESF orange chemical labels?
You don’t have to use the ESF labels, but it is an inexpensive and easy way to know that you are labeling your transferred chemicals completely and properly. If you don’t use them you still have to place that same information on the containers.
You probably do not need an ESF label on a manufacturer's bottle prepared after 1986, as the label contains all necessary information. Just add the date received and the date opened to the manufacturer's information.
How do I maintain MSDSs (Material Safety Data Sheets) for all my chemicals?
Government regulation requires that users of hazardous chemicals maintain health and safety information on all hazardous materials so that all people who may come in contact with them can access the information immediately. This includes all workers as well as visitors to your laboratory, custodial, maintenance or emergency personnel.
One approach is to maintain a paper collection of MSDSs for all hazardous chemicals in your laboratory. An alternative is to bookmark on a computer accessible from your laboratory, a MSDS website. UVM has a site license for the use of the electronic collection at http://ccinfoweb.ccohs.ca/msds/search.html
In addition, the Laboratory Chemical Safety Summaries at http://www.hhmi.org/about/labsafe/lcss.html are likely to provide useful information about the chemicals they cover. Alternatively, many laboratory chemical suppliers provide access to MSDS on their web sites.
If you have hazardous chemicals without specific constituents listed on the label, you must have a paper copy of the MSDS on hand in the laboratory. Make sure your Laboratory Safety Notebook lists how to access or find MSDSs for your laboratory.
Can I keep a chemical past its expiration date?
If it is a time-sensitive material (that becomes dangerous because of peroxide formation or other degradation over time, as listed on Environmental Safety's Laboratory Chemical Inventory) you may not keep it past its manufacturer’s expiration date. If a time sensitive material has no manufacturer’s expiration date, you can calculate by the ‘date received’ placed on it by laboratory workers and the expected shelf life of the material (for example, 12 months for diethyl ether, tetrahydrofuran, or dioxane). If no date is present, it must be considered to be past its expiration date and disposed of accordingly by tagging it with the “Laboratory Waste” tag.
If the chemical is not listed as time sensitive, use professional judgment to ascertain if the chemical is still safe and usable. For example, if a powder is still free-flowing, it may be kept for use. Make sure the labels are maintained and annual inspections are marked on the containers.
How do I know what is a "Time Sensitive Chemical"?
A time sensitive chemical is one that "when stored for prolonged periods or under improper storage conditions can develop hazards that were not present in the original formulation...Peroxide formation is the best known of all time sensitive chemical classes." It is very important that time sensitive chemicals be disposed of when they reach the manufacturer's expiration date. The time sensitive chemicals listed on UVM's Hazardous Chemicals of Concern Inventory are listed below:
- Diisopropyl Ether
- Dioxane
- Ethyl Ether
- Isopropyl Ether
- Tetrahydrofuran
- Potassium, metal
- Chloromethyl Ether
- Chloromethyl Ethyl Ether
- Chloromethyl Methyl Ether
