The invention concerns a novel method for preparing non-toxic resins crosslinkable under radiation in the presence of an initiator system. Said resins are prepared from compositions of an organic and/or silicon type comprising monomers, oligomers and/or polymers with organofunctional groups, and are cross-linked in the presence of an initiator system consisting of an onium salt with low toxicity whereof the cationic structure is [(CH(CH3)2—C6H4—)—I—(—R1)]+(I).