Bomb disposal experts detonated an explosive device found at Harrington Marina's car park.
The "unexplained package" was found on the marina last night.
A bag, described as a computer laptop bag, was spotted by a passer-by in the car park near the seafront, who called the police.
Officers were sent to cordon off the area and stand guard.
They had to wait until this morning for experts to investigate further.
It was a flare and was exploded at around 10am and Cumbria police said there was no risk to the public.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here