Solvents are probably the most common toxins you'll encounter on the job. Consider, for example, adhesive-based assembly of nometallic raceway. While such raceway serves a definite need, adhesives used during field assembly give off solvent vapors as soon as you open the can. These won't hurt you, if you follow the safety practices recommended on the label and in the MSDS.
In addition to adhesives, electricians commonly encounter solvents in the form of cleaning fluids (cleaning electrical contacts) and as paint thinners (touching up enclosures). Trichloroethane 1, 1, 1 (methyl chloroform) is known as "safety solvent" because it doesn't easily ignite. It is not, however, safe to apply to your skin. For one thing, it dissolves your skin's protective oils. Dry skin is far less resistant to bacteria and other invaders. The Trichloroethane itself is toxic and easily absorbed through skin. Trichloroethane is being phased out, but its replacements are also incompatible with human skin.