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A researcher at Darmouth died in June of 1997 from acute mercury poisoning. Her exposure was the result of approximately one-half of a milliliter of dimethyl mercury falling on her hand during an experiment. Although she was wearing latex gloves and replaced them soon after the exposure, within several months she had developed mercury poisoning. The reason for her exposure was that dimethyl mercury easily permeates latex gloves. She and many of her colleagues around the world were totally unaware of this property of dimethyl mercury although they frequently use it.
Do you know if the glove you are using is right for the tasks you do?
First: Determine the Hazard
What is the main hazard? Are you concerned with protection from hazardous chemicals, biological materials, radioactive materials, sharp objects, or a combination of these? Also, consider the length of exposure.
Second: Glove Selection
In general latex and nitrile gloves are by far the most common gloves used in research laboratories on campus. Standard latex exam gloves are cheap and do provide protection for biological and aqueous radioactive hazards. However, you probably won't find them listed in chemical glove selection guides, so, if your main concern is chemical protection then this is not the glove for you. While disposable nitrile gloves are slightly more expensive than latex, you can find glove selection data for some of them.
Chemical Hazard
Look at glove selection guides in catalogues or web sites of various scientific and safety suppliers. Gloves are rated for degradation, breakthrough, and permeation rates. Choose a glove that provides the best resistance to the chemical being used. For some hazards double gloving may be needed. (For example, now the recommended gloves for dimethyl mercury are a highly resistant laminate glove (Silver-Shield or 4H), which has no abrasion/cut resistance, worn under a pair of long cuffed unsupported neoprene, nitrile, or similar heavy-duty glove.) Biological Hazards
Protection from biological hazards may be simple or complex dependent on whether the biological material is immersed in something other than water. Radioactive Hazards
Gloves provide a necessary personal protection barrier and help prevent scatter contamination. Glove selection is based on the carrier material (i.e. water, toluene, etc.). (Radioiodination procedures require double gloving.) Sharps Hazards
Chemical compatibility guides may not indicate susceptibility to abrasion or cuts. You will need to check Mfg. or supplier for this information. Combination Hazard
Selection guides normally list gloves by the protection they provide from one "pure" chemical, not a combination. In this case selection should be based on the component with the shortest breakthrough time.
Glove Selection Resources:
Lab Safety Supply has a downloadable PDF file called Chemical Compatibility Guide for Gloves on their web site at: www.labsafety.com/refinfo/ezfacts/default.htm.
Third: Other Items that Affect Selection
- Higher chemical concentration, higher temperature, or longer exposure time will shorten the breakthrough time.
- Some people have allergic reactions to natural rubber latex, see DHHS [NIOSH] Publication No. 97-135
- Gloves come in more than one length and type of cuff (i.e. how far it extends up the arm and how it fits at the wrist) These are important if you need to protect the wrist as well as hands.
- Gloves come in various sizes. You need to select the size that fits best especially if dexterity is a concern. If dexterity is not a main concern, selecting a slightly larger glove may allow you to slip in and out of a glove if you are doing various tasks-some of which require gloves and some which do not. Gloves that are too small loose dexterity and may not provide the rated protection if the material is stretched thinner to fit.
- Single use gloves must be disposed of properly and never washed and re-used.
NO GLOVE IS IMPERVIOUS!
Know the limitations of the gloves you are using.
Inspect disposable and reusable gloves before each use. Check for swelling, shrinking, cracking, discoloration, holes, or punctures.
Long term exposure, and damage to any glove's surface can quickly reduce the protection offered. Be aware of direct chemical contact, soiled, or torn gloves. They should be removed immediately, the hands should be washed, and gloves replaced with a new pair.
Reusable gloves must be washed before removal, handled only by the cuff, and then properly stored.
Gloves should be removed when picking up a telephone or using equipment others touch bare-handed. Like all personal protective equipment gloves should never be worn outside the laboratory area.
Q. "But I just use my gloves for product protection why do I have to remove them when I run down the hall?"
A. If you are really trying to protect the product you are not doing a very good job since hundreds of other people touch those same door knobs and elevator buttons each day without wearing a glove. Your glove will become as contaminated as your hand would be. Nor should you need to wear gloves while pushing carts through public areas. You need to contain the hazards well enough so that you do not need gloves. Then just carry a pair of reusable gloves with you which you can don as needed.
Contact EHS for additional information on glove selection or personal protective equipment selection.
If you cannot find selection data, the gloves are too thick for dexterity, the cost is prohibitive, etc. - EH&S recommends that you only use "non-recommended" gloves if:
- You check with EH&S for a possible alternative solution.
- Your procedures are such that you never have direct contact between the glove and the hazardous chemical.
- The materials you work with have properties that can serve as a warning of contact before serious harm can occur.
- The materials you work with are not defined as particularly hazardous. (See the UW Lab Safety Manual for a complete definition of particularly hazardous.)
- You change your gloves every 15 minutes.
- If your gloves contact the hazardous material, you immediately remove and dispose of the gloves, wash your hands and put on a new pair.
- Recommended gloves are available and used for spill cleanup and any other non-routine use.
- Recommended gloves are used for new procedures and when training new staff.
- Each person using the non-recommended gloves knows of the limitations of the glove and these precautions.
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