Paradip: Blaring shriek of siren triggered panic at the oil refinery complex here and the "warning" left everybody in a state panic.

The refinery personnel, however, heaved a sigh of relief after coming to know that it was an off-site mock drill exercise to meet with disaster exigencies. An emergency scenario was enacted with the detection of major LPG leak originated from the pipeline fitting of Paradip-Haldia-Durgapur Pipeline complex located on the premises of the refinery.

"The LPG leak was detected and alarm was sounded at their control room from one of the hydrocarbon detectors. The leak from the first isolation valve's upstream flange was envisaged with formation of LPG vapour cloud covering an area of 2.1km up to the refinery main gate No. 2," said the refinery's chief manager (administration and welfare) Manjushree Singh.

The fire and safety team took action for cutting off all sources of ignition. Water curtains were installed around the LPG station to prevent spread of the vapour cloud.

The workers on job were asked to come down safely and proceed to the nearest assembly point. Workshop, main store and warehouses, site office were evacuated swiftly.

The disaster control room and the emergency handling activities were activated.

After 45 minutes of emergency-handling operations, the affected line was de-pressurised and emptied. After restoration of normality, clearance was given for blowing the all-clear siren. The major off-site emergency exercise lasted for 47 minutes.