A beach half a mile away from the UK's largest North Sea gas terminal was sealed off on Saturday after a US Navy flare was found.
A US Navy flare washes up on a beach near Bacton gas terminal
A sea angling competition at Bacton in Norfolk also had to be relocated.
Yarmouth Coastguard said they were advised by the Royal Navy to have the area cleared because if the flare ignited it would produce toxic fumes.
Coastguards are liaising with the Royal Navy bomb disposal team in Portsmouth about its removal.
Watch manager Colin White said: "This flare was found by a member of the public walking his dog who immediately called the authorities.
"If anyone finds anything along the beaches that could be ordnance, do not touch it and call the Coastguard.
"With strong north easterly winds continuing today, there is a possibility of more flares coming ashore."