10/15/2013 04:01 EDT | Updated 01/23/2014 06:58 EST

Package of dummy hand grenades forces evacuation of Sarnia federal building

SARNIA, Ont. - A federal building in Sarnia, Ont., was evacuated Tuesday morning after staff found a package containing hand grenades.

Police cordoned off the building for nearly two hours before determining the grenades were inert.

A provincial police team of explosives experts was dispatched from London, Ont., but turned around when it was found the devices were non-explosive.

Coast Guard employee Lisa Kernohan says an official from Canada Post evacuated all of the federal government departments, including the Coast Guard and Transport Canada.

Police continue to investigate.