SHILLONG: Four persons were injured when a carbide cylinder exploded in a workshop at Mawlai Nongkwar on Tuesday. The incident happened when the workers were engaging at work at the workshop. The injured persons are Donboklang Kharakor (32), Shanborlang Rani (15), Arun Rani (19) and Condius Warjri (18 yrs) All of them were taken to Robert Gordon Hospital, Jaiaw, Shillong for treatment.