"A Saudi and a Filipino died from inhaling nitrogen gas when inspecting a tank belonging to Cristal Titanium Dioxide Co.,” said spokesman of the Civil Defense in Madinah Lt. Col. Khaled Al-Johani in a statement.

Another worker accompanying them suffered serious breathing problem, Al-Johani added. The injured worker was taken to the Royal Commission Medical Center.

With the help of three Civil Defense rescue teams the bodies were retrieved from the tank. The workers had gone down the tank without obtaining previous approval from safety officials, Al-Johani added.