The continuing danger from lost world-war mines

Are any First or Second World War minefields still dangerous?

Not as coherent minefields, but lost individual mines still turn up and can remain hazardous.

Many mines were never recovered after the world wars, and individual examples still wash ashore. Their condition depends partly on whether the explosive compartment has remained sealed. Seawater intrusion may have degraded the charge, while a sealed charge can remain dangerous and become more sensitive as it ages. An old exterior gives no reliable assurance that a mine is harmless. The advice is to keep well clear of a suspected mine and leave it to bomb-disposal personnel.