Protective Gloves for Epoxy
by Philip Jacobs
A number of my safety and health colleagues are also boaters, and when we meet the conversation often winds to points where these interests cross, such as the ergonomics of paddling, or the toxicity of building materials.
So I was expecting a quick and conclusive reply recently, when I asked an industrial hygienist contact which types of protective gloves to use when working with epoxy resins and hardeners. His guarded response was less than satisfying, and set off a search which, like under-catalyzed resin in a cold Minnesota garage, has yet to fully yield something solid and usable.
Boatbuilders expose themselves to certain hazards. Some safety hazards, such as the use of hand and power tools, are common to general woodworking and are easily recognizable. Respiratory effects of cedar and other wood dusts are less obvious, and have been noted in earlier HUTS! In addition to inhaling solvent vapors, as noted in the MCA builder's manual, some chemicals can be absorbed directly through the skin, with possible short term reactions and unknown long term consequences.
Epoxies, specifically, are known to cause allergic reactions in some people on contact, and when airborne concentrations of resin components or uncured sandingdust is inhaled. Some people develop these allergies over time through a process known as 'sensitization'. Once sensitized, the individual may experience increasingly severe reactions, so prevention is prudent, especially if one wants to build additional boats.
Exactly what is appropriate protection was not easy to find. Using a NIOSH database and MEDLINE, matching keywords 'epoxy' and 'gloves' provided several research articles on the topic. Apparently, not all epoxies are formulated the same, and different components of the resins and hardeners were of interest to different researchers.
One promising article placed drops of an epoxy component on samples of several glove fabrics in a laboratory, and measured the time until 'breakthrough'; however, it noted in a follow-up experiment that breakthrough occurred in a fraction of these times when workers with body heat applied pressure with the gloves on an epoxy coated surface or tool.
Some multi-layered glove materials exhibited excellent protection against breakthrough, however, these stiff composites provide all of the dexterity of working with one's hands inside empty potato chip bags. For almost any material, thicker gloves generally provide more protection against breakthrough-- at a cost of dexterity, but unless impervious, must also be replaced after a period of use.
The effectiveness of barrier creams, applied directly to the skin, was not addressed extensively in the articles reviewed, although its use as a substitute for gloves has to be viewed with skepticism. Barrier cream worn under gloves may offer a secondary defense against absorption, especially if the skin is dry or cracked, and may be considered as part of a protective 'system'.
Two gloves commonly mentioned in the articles were latex, such as those commonly used for medical exams, and nitrile, which are also available in thin styles (4 to 5 mils thick) used in a disposable manner. Comparison of these two gloves became the renewed focus of the quest.
It should be noted that nitrile generally exhibited longer breakthrough times in the articles, suggesting more protection. However, it is not clear if the added protection is meaningful for the limited use of glassing a canoe hull, or whether latex is "good enough". It should also be noted that these findings are for epoxy only. Nitrile, for example, is not recommended for protection against acetone, a solvent commonly used to clean off resin accidentally spilled on tools, floors, house pets, etc. Latex on the other hand, has recently been shown to cause its own allergic sensitization in some individuals, to the point that some medical kit manufacturers are switching to nitrile gloves.
Seeking practical advice, technical representatives from the makers of West System (517/684-7286 or www.cris.com/~gougeon) and AD-TECH (800/255-9934 or www.adtechplastics.com) epoxies were contacted. Each stated that both latex and nitrile gloves are used extensively at their own facilities as a matter of practice. The Material Safety Data Sheets (MSDS) for these products recommend 'plastic or rubber gloves', which is slightly more specific than the terms 'protective' or 'impervious gloves' used on other MSDS, according to one article which specifically advised against use of PVC gloves for epoxies.
The bottom line has yet to be written, but a sensible strategy should include the following steps: 1) Find out what the manufacturer is currently recommending for the specific resins and hardeners used. Ask for an MSDS or speak with one of their representatives. 2) Use protective gloves, along with other safety precautions, when using epoxy resins. Latex and nitrile gloves appear to be appropriate for home canoe building use. 3) Change gloves frequently, especiallywhen using thin, examination style gloves, and do not re-use them. 4) Barrier creams worn under gloves may offer some additional protection, especially for dry or chapped hands.
Thin latex (about $7 to $12 per 100 gloves) and nitrile gloves (about $15 to $18 per 100 gloves) are available from local safety suppliers, such as Elvin Safety Supply (800/373-5846), or catalogs such as Lab Safety Supply (800/356-0783).
