Residents in Saltcoats, Ardrossan and Stevenston were sent into a panic on Wednesday, March 2, after many heard what was desrcibed as a "WWII air raid siren".
It could be heard as far afield as Kilwinning and Pennyburn with many taking their confusion to social media.
Given the current situation in Russia and Ukraine, locals were understandly jumping to conclusions.
The similarities between the sound heard, and a WWII air raid siren are clear.
The Herald can confirm, for anyone unaware of exactly what the siren was, that it was a routine test, carried out by Chemring Energetics on their plant in Ardeer industrial estate.
A spokesperson said: "The siren is the muster alarm test which is performed every month and is part of our emergency response tests as part of a COMAH tier 1 site.
"It is designed to warn our staff of an event on site and prompts them to gather in designated muster points for a roll call.
"Due to the size of the Ardeer site and the need for all staff to be able to hear the siren wherever they are at that point in time, the siren is understandably loud.
"There is no cause for local residents to be alarmed, this is a standard procedure.
"Due to restrictions caused by Covid, meaning that we could not gather staff together in enclosed spaces, the tests were stopped for a number of months but have been running again since the start of 2022 and should be expected to continue into the future."
This test typically takes place on the first Wednesday of every month, at around 10am.
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