Four workers were killed on Sunday night in a quarry landslide in Egypt's South Sinai governorate, Ahram Arabic website reported.
Initial investigations revealed that the workers, all from Upper Egypt's Sohag governorate, were not using safety equipment and were not properly trained to work in the quarry.
The medical examination found that the workers died of asphyxiation.
The stone pit, which is located in Ras Sedr's Abu-Gaadai, produces glass sand. It is owned by the government and rented to private contractors.