Outdoor hazards are obvious such as: volume
of traffic, incidence
of disease, a
cat's ability to protect itself (deaf, partially
sighted, frail), its danger to other
cats (if it has a transmissible disease), predation upon vulnerable wildlife, any danger to humans (a British
cat, Gizmo the postman hater, had to be confined for the safety
of postmen and other delivery men), danger from humans (e.g. gamekeepers), spilt car antifreeze and garden chemicals.