Several others have been injured.
From Shama, Dotsey Koblah Aklorbortu reports that the explosion occurred at a quarry site of G-Omini Quarry in the Shama District of the Western Region.
Many night shift workers said to be Ghanaian and Chinese nationals have been burnt, some beyond recognition.
The explosion, occurred at about 00:30 GMT.
The explosives, reportedly being kept at an unstructured storage without permit detonated and killed the workers, Graphic Online’s Dotsey Koblah Aklorbortu reports.
Aside the fatalities and injuries, it has caused extensive damage to the quarry.
The District Chief Executive for Shama, Ebenezer Dadzie confirmed the incident to Graphic Online and said efforts were underway to rescue those missing and also assess the extent of damage.
He said the District Security Council was yet to put a number to the injured and fatalities.
Graphic Online has however gathered from sources that the company was storing the explosives illegally without the permission of the Minerals Commission contrary to the law governing the acquisition, storage and use of explosives.
A source close to the company said, the explosion did not occur in the process of blasting but rather the yet to be used explosives kept in a room which is not a structured storage explosive magazine.
It said the casualties were workers who were on a night shift and were busy going about their routine activities at that time of the explosion.