The three routes in
Updated
On this page7
Skin, which is the main one
Direct contact with uncured resin or hardener, and it happens far more often than people count: a thumb on the rim of a cup, a drip on a wrist, picking up a piece that is hard but not cured, wiping a mold. Each is trivial and they add up, which is the whole mechanism from the previous page.
Airborne, which depends on the product
Some systems release more vapor than others and warm resin releases more than cool. A sealed room with no extraction concentrates whatever there is, and the absence of a strong smell is not evidence of absence. Section 8 of the data sheet tells you whether a respirator is called for.
Dust, which is the forgotten one
Sanding and machining cured work makes fine dust, and if the piece is not fully cured that dust carries reactive material. Even fully cured, it is respirable dust you do not want. Extraction at the tool beats a mask after the fact.
Cleanup is an exposure, not the end of one
Wiping tools and cups with solvent spreads resin thinly over a large area of hand and rag, and solvent on skin helps carry material through it. Letting waste resin cure and then discarding it solid avoids the whole episode and is the better habit.
Never clean skin with solvent
It defeats the barrier the skin provides and drives material into it. Soap and water, promptly, is the answer, and a resin-specific skin cleanser if you want one. This is the single most common bad habit in the craft.
Work out which route your setup actually has
A maker doing small cold pours with good gloves has a different profile from one doing deep pours in a closed room, or one sanding daily. The controls should follow which route is live in your workshop rather than a generic list.