The most common form of reaction is contact dermatitis, a rash similar to that produced by poison oak. Some people are more sensitive than others, and the sensitization process is curious. You can work with the stuff for years and never have a reaction, but you can become sensitized at any time, and from then forward you will remain sensitized. This applies only to the unreacted components though; cured epoxy is practically inert. But remember that full cure can take a very long time.

Prevention is clearly the best method of coping with the risks. Ventilation of the workspace is important. Gloves and respirator with Organic Vapor cartridges are minimum precautions, in my opinion. Barrier creams are good too, as are Tyvek coveralls.

: I know epoxy is one of those things you'd like to avoid and should only use
: with good ventilation, and of course that it's physical effects are far
: outweighed by a kayaks mental effects, but how bad is it and what does it
: do?