CBRN event in Pakistan on Mon 5th August 1996

On August 5, 20 and 21, unusual high activity up to 2203 Bq/m3 was reported by the Health Physics surveyor in the I-131 plant room during routine air sampling. Investigations revealed that the ventilation of the building was shut down during off-working hours. Due to the closure of exhaust/ventilation system, the negative pressure in I-131 cell was lost and the pressure in the cell became in equilibrium with room pressure, thereby by un-utilized Iodine-131 vapors in the fume hoods diffused and escaped the cell causing spread of radioactivity in the plant room. The Iodine-131 released ws from the left-over of the process. Had it been the total amount of Iodine which is 10 Curies (designed capacity of the plant) the situation would have been more severe.