Four Pakistani workers were killed and a fifth badly injured when an abandoned airliner they were working on exploded at Taif Airport on Saturday afternoon. According to the General Authority of Civil Aviation (GACA) the accident occurred when the five workers were dismantling a decommissioned Tristar aircraft that lay abandoned at the airport for spare parts. The five men were working for Regency Projects, a UK-registered company based in London that works on some aviation projects in Taif. Saturday's explosion is believed to have been caused by a leak in a tank in the starboard wing of the aircraft. The tank, and then the entire wing, caught fire as the men were working on it. GACA said in a statement that the blast occurred at about 4:15 P.M Saturday at a remote spot of the airport's premises. Firefighting teams of the GACA rushed to the scene and put out the fire and evacuated the injured worker. A source at the Taif Airport, who spoke on condition of anonymity, said that the five company employees might have had some welding work near the fuel tank. The Civil Aviation Authority and airport officials did not provide the names of the four dead workers or the injured one. Abdul Hameed Abu Al-Ara, spokesman for the General Authority of Civil Aviation headquarters in Jeddah, told Saudi Gazette that an investigation team was formed to find out more details about the accident. “We have our own Safety team, and the British company will not interfere in the investigations,” said Abu Al-Ara. “We will issue another statement in the coming days (with) more details.” According to Abu- Ara, Air traffic at the airport went uninterrupted. Mohammed Asiri, a relative of a passenger who was on his way into the airport when the old aircraft exploded, said the sound of the blast was not very loud. “I heard something in the back yard of the airport,” Asiri said. Representatives of Regency Projects, the UK company for which the five employees worked, were not readily available for comment. The company, which has been providing shipping management services and the trading of decommissioned vessels for over a decade, has representative offices in Alexandria, Fujairah, Karachi and Taif. The company has only recently venturd into the oil business and buying and selling old aircraft. It has a fleet of 15 320-seat Tristars. __