EPS and XPS produce mostly styrene + CO2 when melted with a clean wire. EPP and PE are cleaner. Polyurethane foam is BAD — it produces isocyanates and HCN; do not cut PU with a hot-wire.
Minimum: ventilation (open window + small fan blowing fumes away). Better: a cardboard hood + ducted exhaust to outdoors. Best: a small particulate respirator (N95 or FFP2) if cutting more than 10 min/day. None of this is paranoid — it's the same advice as for hot-melt glue.
Minimum: ventilation (open window + small fan blowing fumes away). Better: a cardboard hood + ducted exhaust to outdoors. Best: a small particulate respirator (N95 or FFP2) if cutting more than 10 min/day. None of this is paranoid — it's the same advice as for hot-melt glue.