Reactive Process Safety, Exotherm and Fire Risk in Photoresin Manufacture and Use

Photoresin manufacture and use combine reactive unsaturated monomers or oligomers, photoinitiators, inhibitors, pigments, fillers, solvents and, in some systems, thermal initiators or second-stage curing chemistry. The same kinetic features exploited for rapid cure can create process-safety liabilities when reaction rate and heat generation rise faster than heat can be removed. This review develops a qualification framework for reactive safety across compounding, hold, storage excursion, post-cure and printer-adjacent operations. Primary and review evidence from radical-polymerisation runaway and inhibition studies shows that inhibitor state and loss of heat removal can materially change escalation behaviour. The review separates four questions that are often conflated: whether a formulation can self-heat or run away; whether volatile or decomposing species can generate pressure; whether vapours or liquids are ignitable; and whether an emergency intervention is technically defensible for the exact chemistry. It proposes a minimum evidence set based on composition state, calorimetry, kinetic interpretation, heat-transfer context, credible-deviation analysis and scale-specific acceptance criteria. No universal safe temperature, inhibitor concentration, batch size or emergency-quench recipe is proposed because those quantities are formulation- and equipment-specific.