Just picked one up today to test out. Says on the package - "clear liquid plastic - hardens with UV light". Is a modified acrylamide and mixed acrylates. Warning label says - "Liquid causes serious eye damage. Eye, skin and respiratory irritant. Do not breathe vapor. Keep away from heat and flames. UV light can burn eyes and skin. Do not point at people or animals. Keep away from children, Prevent contact with eyes, skin and clothing".
Seems some care in use is appropriate, just like using other adhesives, paints, thinners etc. I myself will sometimes get a reaction to CA glue when using lots of it in building wood models. I get symptoms just like a cold, although an allergy pill relieves the symptoms quickly.
Gonna test it on plastic and wood tomorrow, report to follow.
EJ