THREE BAE Systems engineers were injured after a warship gun misfired during testing.
The workers were aboard the Portsmouth-built Omani warship Al-Shamikh which was being tested off the Dorset coast.
Reports said there was an explosion on board, but BAE insists that was an exaggeration and denied suggestions of a fire.
The men were taken to hospital as a precautionary measure and discharged the same day, a BAE spokeswoman said.
The incident near Portland Port happened on Sunday, March 11, but details have only just emerged.
The ship was undergoing sea trials in the English Channel before being handed over to the Sultanate of Oman Navy later this year.
A spokeswoman for BAE said: ‘An incident occurred on board Al-Shamikh while on sea trials on Sunday during test firings.
‘The ship returned to shore safely and an investigation is under way.’
A South West Ambulance Service spokesman said: ‘There were three male casualties who were taken to Dorset County Hospital and a number of walking wounded who suffered minor injuries.’