The bomb squad were called in after an explosive was pulled from a canal under a bridge.
Emergency services swarmed the scene on Bank Bridge in Tarleton and closed the road in both directions between Coe Lane and Carr House Lane, at around 4pm today.
The incident was sparked when a rusty grenade was pulled from the Leeds Liverpool canal where Rob Trowler claims he was fishing at the time.
The 29-year-old from Ormskirk told LancsLive : " I was with my friend. It’s the first time I’ve magnet fished at that bridge but I magnet fish I few times a week.
“I realised about 10 seconds after pulling it out it was a grenade but it took a couple of minutes to be 100%.”
Magnet fishers, who use large magnets to pull metal objects from rivers and canals, often make discovers like these.
The magnets used are strong enough to remove large debris such as discarded bicycles, guns, safes, bombs, coins and car tire rims from bodies of water, but many who engage in the hobby are hoping to find rare and valuable items as well.
At 4.30pm a spokesperson for Lancashire Police said: "A grenade has been found in the canal resulting in emergency road closures and a cordon being put into place.
"Please stay away!"
Pictures taken at the scene show the bomb disposal squad carrying out a controlled explosion in a field nearby the scene where the grenade was found.
Roads were reopened at around 6.30pm and a spokesperson for police said: "EOD have recovered the device and the roads are now reopened.
"Thank you all so much for your patience this evening! Please drive safe and apologies for the disruption caused! "
