Updated

A man fishing in a Massachusetts pond near a factory that once tested explosive munitions for the Vietnam War – last week hooked an unexploded device, The Patriot Ledger reported.

The man’s discovery prompted city officials to close off the pond and bring in a safety crew.

The nearby factory that tested munitions closed in 1970, but a collection of explosive devices was left behind, officials said.

Sections of the surrounding area were closed in May 2017 to detonate leftover devices and clean up contaminated soil. Last month, the town closed off all surrounding trails leading to the area, but the pond was still accessible to some residents. 

City officials said the pond will remain closed until they can guarantee the public’s safety.

“It’s become more clear now that there are munitions in the water and we definitely want to make sure that the public is safe,” said Hanover’s town manager.

Nearby residents say house-shaking blasts, have been a common occurrence since a bomb squad team began detonating devices last year, CBS Boston reported.

“Apparently they find ordnance out there and they set it off and I mean it is really loud when it goes off,” said one resident.

Police have warned people to be careful.

“We want people to take it serious, we want people to understand that there’s certainly an element of danger,” police said.

Authorities have not said how long the cleanup will take.