Police in South Florida evacuated a Goodwill store for 90 minutes after a grenade was found in a donation bin, TCPalm reported.

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It was the second time in 10 months that a grenade had been found in a bin at a Port St. Lucie site, the website reported.

Police also evacuated the parking lot at the store as the St. Lucie County Bomb Squad investigated, according to WPTV. A technician who examined the device determined it was inert, the television station reported.

It was not clear who donated the grenade.

Employees at the Goodwill store called 911 Wednesday after the grenade was found in the bin, Port St. Lucie Police spokeswoman Sgt. Lisa Carrasquillo told TCPalm.

An inert grenade was found July 27 at a different Port St. Lucie location, the website reported.

Gulfstream Goodwill spokesman Brian Edwards said the thrift stores do not accept any weapons as donations.

"We were very fortunate the grenade was not triggered," Edwards told TCPalm.